Chore: Add grafana-apiserver (#70721)

* add grafana-apiserver
* remove watchset & move provisioning and http server to background
services
* remove scheme
* otel fixes (#70874)
* remove module ProvideRegistry test
* use certgenerator from apiserver package
* Control collector/pdata from going to v1.0.0-rc8 (as Tempo 1.5.1 would have it)

pkg/services/contexthandler/contexthandler_test.go

@@ -115,3 +115,9 @@ func (mw mockWriter) Before(web.BeforeFunc) {}
 func (mw mockWriter) Push(target string, opts *http.PushOptions) error {
 	return nil
 }
+func (mw mockWriter) CloseNotify() <-chan bool {
+	return make(<-chan bool)
+}
+func (mw mockWriter) Unwrap() http.ResponseWriter {
+	return mw
+}