Implement OFREP compatible feature flag service (#105632)

* Add ofrep pkg

* api server: Use namespace from request in case user is not authenticated

* Add handlers to ofrep api builder

* Add NewOpenFeatureService to initialize mt apiserver

* allow specifying CA and insecure

* Compare namespace with eval ctx stackID

* Organize ofrep package

* Implement AllowedV0Alpha1Resources

* Revert folderimpl changes

* Handle default namespace

* Fix extracting stack id from eval ctx

* Add more logs

* Update pkg/registry/apis/ofrep/register.go

Co-authored-by: Dave Henderson <dave.henderson@grafana.com>

* Update pkg/registry/apis/ofrep/register.go

Co-authored-by: Dave Henderson <dave.henderson@grafana.com>

* Apply review feedback

* Replace contexthandler with types

* Fix identifying authed request

* Refactor checks in the handlers

* Remove anonymous from isAuthenticatedRequest check

---------

Co-authored-by: Todd Treece <360020+toddtreece@users.noreply.github.com>
Co-authored-by: Gabriel Mabille <gabriel.mabille@grafana.com>
Co-authored-by: Charandas Batra <charandas.batra@grafana.com>
Co-authored-by: Dave Henderson <dave.henderson@grafana.com>

pkg/server/wire.go

@@ -324,6 +324,7 @@ var wireBasicSet = wire.NewSet(
 	featuremgmt.ProvideManagerService,
 	featuremgmt.ProvideToggles,
 	featuremgmt.ProvideOpenFeatureService,
+	featuremgmt.ProvideStaticEvaluator,
 	dashboardservice.ProvideDashboardServiceImpl,
 	wire.Bind(new(dashboards.PermissionsRegistrationService), new(*dashboardservice.DashboardServiceImpl)),
 	dashboardservice.ProvideDashboardService,