Plugins: Core plugins register via backend factory provider (#43171)

* refactoring store interface and init flow

* fix import

* fix linter

* refactor resource calling

* load with class

* re-order args

* fix tests

* fix linter

* remove old creator

* add custom config struct

* fix some tests

* cleanup

* fix

* tackle plugins

* fix linter

* refactor and fix test

* add connect failure error

* add fix for azure, cloud monitoring and test data

* restructure

* remove unused err

* add fake tracer for test

* fix grafana ds plugin

pkg/tsdb/testdatasource/resource_handler.go

@@ -15,13 +15,15 @@ import (
 	"github.com/grafana/grafana-plugin-sdk-go/backend/resource/httpadapter"
 )
 
-func (s *Service) RegisterRoutes(mux *http.ServeMux) {
+func (s *Service) registerRoutes() *http.ServeMux {
+	mux := http.NewServeMux()
 	mux.HandleFunc("/", s.testGetHandler)
 	mux.HandleFunc("/scenarios", s.getScenariosHandler)
 	mux.HandleFunc("/stream", s.testStreamHandler)
 	mux.Handle("/test", createJSONHandler(s.logger))
 	mux.Handle("/test/json", createJSONHandler(s.logger))
 	mux.HandleFunc("/boom", s.testPanicHandler)
+	return mux
 }
 
 func (s *Service) testGetHandler(rw http.ResponseWriter, req *http.Request) {