gokrazy,tstest/integration/nat: add Gokrazy appliance just for natlab

... rather than abusing the generic tsapp.

Per discussion in https://github.com/gokrazy/gokrazy/pull/275

It also means we can remove stuff we don't need, like ntp or randomd.

Updates #13038

Change-Id: Iccf579c354bd3b5025d05fa1128e32f1d5bde4e4
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

gokrazy/tsapp/config.json

@@ -13,8 +13,7 @@
         "github.com/gokrazy/serial-busybox",
         "github.com/gokrazy/breakglass",
         "tailscale.com/cmd/tailscale",
-        "tailscale.com/cmd/tailscaled",
-        "tailscale.com/cmd/tta"
+        "tailscale.com/cmd/tailscaled"
     ],
     "PackageConfig": {
         "github.com/gokrazy/breakglass": {
@@ -31,4 +30,4 @@
     "KernelPackage": "github.com/tailscale/gokrazy-kernel",
     "FirmwarePackage": "github.com/tailscale/gokrazy-kernel",
     "InternalCompatibilityFlags": {}
-}
+}