cmd/k8s-operator: add a kubernetes operator.

This was initially developed in a separate repo, but for build/release
reasons and because go module management limits the damage of importing
k8s things now, moving it into this repo.

At time of commit, the operator enables exposing services over tailscale,
with the 'tailscale' loadBalancerClass. It also currently requires an
unreleased feature to access the Tailscale API, so is not usable yet.

Updates #502.

Signed-off-by: David Anderson <danderson@tailscale.com>

go.mod

@@ -71,7 +71,7 @@ require (
 	golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4
 	golang.org/x/sys v0.2.0
 	golang.org/x/term v0.2.0
-	golang.org/x/time v0.0.0-20211116232009-f0f3c7e86c11
+	golang.org/x/time v0.0.0-20220609170525-579cf78fd858
 	golang.org/x/tools v0.2.0
 	golang.zx2c4.com/wintun v0.0.0-20211104114900-415007cec224
 	golang.zx2c4.com/wireguard/windows v0.5.3
@@ -79,7 +79,11 @@ require (
 	honnef.co/go/tools v0.4.0-0.dev.0.20220517111757-f4a2f64ce238
 	inet.af/peercred v0.0.0-20210906144145-0893ea02156a
 	inet.af/wf v0.0.0-20220728202103-50d96caab2f6
+	k8s.io/api v0.25.0
+	k8s.io/apimachinery v0.25.0
 	nhooyr.io/websocket v1.8.7
+	sigs.k8s.io/controller-runtime v0.13.1
+	sigs.k8s.io/yaml v1.3.0
 	software.sslmate.com/src/go-pkcs12 v0.2.0
 )
 
@@ -96,6 +100,8 @@ require (
 	github.com/Masterminds/sprig v2.22.0+incompatible // indirect
 	github.com/OpenPeeDeeP/depguard v1.0.1 // indirect
 	github.com/ProtonMail/go-crypto v0.0.0-20211112122917-428f8eabeeb3 // indirect
+	github.com/PuerkitoBio/purell v1.1.1 // indirect
+	github.com/PuerkitoBio/urlesc v0.0.0-20170810143723-de5bf2ad4578 // indirect
 	github.com/acomagu/bufpipe v1.0.3 // indirect
 	github.com/alexkohler/prealloc v1.0.0 // indirect
 	github.com/ashanbrown/forbidigo v1.2.0 // indirect
@@ -131,18 +137,25 @@ require (
 	github.com/docker/distribution v2.8.1+incompatible // indirect
 	github.com/docker/docker v20.10.16+incompatible // indirect
 	github.com/docker/docker-credential-helpers v0.6.4 // indirect
+	github.com/emicklei/go-restful/v3 v3.8.0 // indirect
 	github.com/emirpasic/gods v1.12.0 // indirect
 	github.com/esimonov/ifshort v1.0.3 // indirect
 	github.com/ettle/strcase v0.1.1 // indirect
+	github.com/evanphx/json-patch/v5 v5.6.0 // indirect
 	github.com/fatih/color v1.13.0 // indirect
 	github.com/fatih/structtag v1.2.0 // indirect
-	github.com/fsnotify/fsnotify v1.5.1 // indirect
+	github.com/fsnotify/fsnotify v1.5.4 // indirect
 	github.com/fzipp/gocyclo v0.3.1 // indirect
 	github.com/gliderlabs/ssh v0.3.3 // indirect
 	github.com/go-critic/go-critic v0.6.1 // indirect
 	github.com/go-git/gcfg v1.5.0 // indirect
 	github.com/go-git/go-billy/v5 v5.3.1 // indirect
 	github.com/go-git/go-git/v5 v5.4.2 // indirect
+	github.com/go-logr/logr v1.2.3 // indirect
+	github.com/go-logr/zapr v1.2.3 // indirect
+	github.com/go-openapi/jsonpointer v0.19.5 // indirect
+	github.com/go-openapi/jsonreference v0.19.5 // indirect
+	github.com/go-openapi/swag v0.19.14 // indirect
 	github.com/go-toolsmith/astcast v1.0.0 // indirect
 	github.com/go-toolsmith/astcopy v1.0.0 // indirect
 	github.com/go-toolsmith/astequal v1.0.1 // indirect
@@ -153,6 +166,7 @@ require (
 	github.com/go-xmlfmt/xmlfmt v0.0.0-20211206191508-7fd73a941850 // indirect
 	github.com/gobwas/glob v0.2.3 // indirect
 	github.com/gofrs/flock v0.8.1 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/golangci/check v0.0.0-20180506172741-cfe4005ccda2 // indirect
 	github.com/golangci/dupl v0.0.0-20180902072040-3e9179ac440a // indirect
@@ -165,7 +179,9 @@ require (
 	github.com/golangci/revgrep v0.0.0-20210930125155-c22e5001d4f2 // indirect
 	github.com/golangci/unconvert v0.0.0-20180507085042-28b1c447d1f4 // indirect
 	github.com/google/btree v1.0.1 // indirect
+	github.com/google/gnostic v0.5.7-v3refs // indirect
 	github.com/google/go-containerregistry v0.9.0 // indirect
+	github.com/google/gofuzz v1.1.0 // indirect
 	github.com/google/goterm v0.0.0-20200907032337-555d40f16ae2 // indirect
 	github.com/google/rpmpack v0.0.0-20201206194719-59e495f2b7e1 // indirect
 	github.com/gordonklaus/ineffassign v0.0.0-20210914165742-4cc7213b9bc8 // indirect
@@ -186,6 +202,7 @@ require (
 	github.com/jingyugao/rowserrcheck v1.1.1 // indirect
 	github.com/jirfag/go-printf-func-name v0.0.0-20200119135958-7558a9eaa5af // indirect
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
 	github.com/josharian/native v1.0.1-0.20220222152702-a938fb150d47 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/julz/importas v0.0.0-20210922140945-27e0a5d4dee2 // indirect
@@ -201,10 +218,11 @@ require (
 	github.com/ldez/gomoddirectives v0.2.2 // indirect
 	github.com/ldez/tagliatelle v0.2.0 // indirect
 	github.com/magiconair/properties v1.8.5 // indirect
+	github.com/mailru/easyjson v0.7.6 // indirect
 	github.com/maratori/testpackage v1.0.1 // indirect
 	github.com/matoous/godox v0.0.0-20210227103229-6504466cf951 // indirect
 	github.com/mattn/go-runewidth v0.0.13 // indirect
-	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.2-0.20181231171920-c182affec369 // indirect
 	github.com/mbilski/exhaustivestruct v1.2.0 // indirect
 	github.com/mdlayher/socket v0.2.3 // indirect
 	github.com/mgechev/dots v0.0.0-20210922191527-e955255bf517 // indirect
@@ -213,7 +231,10 @@ require (
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
 	github.com/mitchellh/mapstructure v1.4.3 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/moricho/tparallel v0.2.1 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/nakabonne/nestif v0.3.1 // indirect
 	github.com/nbutton23/zxcvbn-go v0.0.0-20210217022336-fa2cb2858354 // indirect
 	github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646 // indirect
@@ -228,7 +249,7 @@ require (
 	github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/polyfloyd/go-errorlint v0.0.0-20211125173453-6d6d39c5bb8b // indirect
-	github.com/prometheus/client_golang v1.11.0 // indirect
+	github.com/prometheus/client_golang v1.12.2 // indirect
 	github.com/prometheus/client_model v0.2.0 // indirect
 	github.com/prometheus/common v0.32.1 // indirect
 	github.com/prometheus/procfs v0.7.3 // indirect
@@ -273,18 +294,33 @@ require (
 	github.com/x448/float16 v0.8.4 // indirect
 	github.com/xanzy/ssh-agent v0.3.1 // indirect
 	github.com/yeya24/promlinter v0.1.0 // indirect
+	go.uber.org/atomic v1.7.0 // indirect
+	go.uber.org/multierr v1.6.0 // indirect
+	go.uber.org/zap v1.21.0 // indirect
 	golang.org/x/exp/typeparams v0.0.0-20220328175248-053ad81199eb // indirect
 	golang.org/x/image v0.0.0-20201208152932-35266b937fa6 // indirect
 	golang.org/x/mod v0.6.0 // indirect
+	golang.org/x/oauth2 v0.0.0-20220411215720-9780585627b5 // indirect
 	golang.org/x/text v0.4.0 // indirect
+	gomodules.xyz/jsonpatch/v2 v2.2.0 // indirect
+	google.golang.org/appengine v1.6.7 // indirect
 	google.golang.org/protobuf v1.28.0 // indirect
+	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/ini.v1 v1.66.2 // indirect
 	gopkg.in/warnings.v0 v0.1.2 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	howett.net/plist v1.0.0 // indirect
+	k8s.io/apiextensions-apiserver v0.25.0 // indirect
+	k8s.io/client-go v0.25.0 // indirect
+	k8s.io/component-base v0.25.0 // indirect
+	k8s.io/klog/v2 v2.70.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20220803162953-67bda5d908f1 // indirect
+	k8s.io/utils v0.0.0-20220728103510-ee6ede2d64ed // indirect
 	mvdan.cc/gofumpt v0.2.0 // indirect
 	mvdan.cc/interfacer v0.0.0-20180901003855-c20040233aed // indirect
 	mvdan.cc/lint v0.0.0-20170908181259-adc824a0674b // indirect
 	mvdan.cc/unparam v0.0.0-20211002134041-24922b6997ca // indirect
+	sigs.k8s.io/json v0.0.0-20220713155537-f223a00ba0e2 // indirect
+	sigs.k8s.io/structured-merge-diff/v4 v4.2.3 // indirect
 )