feat(api): feature flags (#7356)

* feat(api): feature API proto definitions

* update proto based on discussion with @livio-a

* cleanup old feature flag stuff

* authz instance queries

* align defaults

* projection definitions

* define commands and event reducers

* implement system and instance setter APIs

* api getter implementation

* unit test repository package

* command unit tests

* unit test Get queries

* grpc converter unit tests

* migrate the V1 features

* migrate oidc to dynamic features

* projection unit test

* fix instance by host

* fix instance by id data type in sql

* fix linting errors

* add system projection test

* fix behavior inversion

* resolve proto file comments

* rename SystemDefaultLoginInstanceEventType to SystemLoginDefaultOrgEventType so it's consistent with the instance level event

* use write models and conditional set events

* system features integration tests

* instance features integration tests

* error on empty request

* documentation entry

* typo in feature.proto

* fix start unit tests

* solve linting error on key case switch

* remove system defaults after discussion with @eliobischof

* fix system feature projection

* resolve comments in defaults.yaml

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>

internal/api/grpc/feature/v2/server.go

@@ -0,0 +1,47 @@
+package feature
+
+import (
+	"google.golang.org/grpc"
+
+	"github.com/zitadel/zitadel/internal/api/authz"
+	"github.com/zitadel/zitadel/internal/api/grpc/server"
+	"github.com/zitadel/zitadel/internal/command"
+	"github.com/zitadel/zitadel/internal/query"
+	feature "github.com/zitadel/zitadel/pkg/grpc/feature/v2beta"
+)
+
+type Server struct {
+	feature.UnimplementedFeatureServiceServer
+	command *command.Commands
+	query   *query.Queries
+}
+
+func CreateServer(
+	command *command.Commands,
+	query *query.Queries,
+) *Server {
+	return &Server{
+		command: command,
+		query:   query,
+	}
+}
+
+func (s *Server) RegisterServer(grpcServer *grpc.Server) {
+	feature.RegisterFeatureServiceServer(grpcServer, s)
+}
+
+func (s *Server) AppName() string {
+	return feature.FeatureService_ServiceDesc.ServiceName
+}
+
+func (s *Server) MethodPrefix() string {
+	return feature.FeatureService_ServiceDesc.ServiceName
+}
+
+func (s *Server) AuthMethods() authz.MethodMapping {
+	return feature.FeatureService_AuthMethods
+}
+
+func (s *Server) RegisterGateway() server.RegisterGatewayFunc {
+	return feature.RegisterFeatureServiceHandler
+}