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/plugins/manager/loader/loader_test.go

@@ -15,6 +15,8 @@ import (
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/models"
 	"github.com/grafana/grafana/pkg/plugins"
+	"github.com/grafana/grafana/pkg/plugins/backendplugin"
+	"github.com/grafana/grafana/pkg/plugins/backendplugin/coreplugin"
 	"github.com/grafana/grafana/pkg/plugins/backendplugin/provider"
 	"github.com/grafana/grafana/pkg/plugins/manager/loader/finder"
 	"github.com/grafana/grafana/pkg/plugins/manager/loader/initializer"
@@ -904,7 +906,7 @@ func newLoader(cfg *plugins.Cfg) *Loader {
 	return &Loader{
 		cfg:                cfg,
 		pluginFinder:       finder.New(),
-		pluginInitializer:  initializer.New(cfg, &provider.Service{}, &fakeLicensingService{}),
+		pluginInitializer:  initializer.New(cfg, provider.ProvideService(coreplugin.NewRegistry(make(map[string]backendplugin.PluginFactoryFunc))), &fakeLicensingService{}),
 		signatureValidator: signature.NewValidator(&signature.UnsignedPluginAuthorizer{Cfg: cfg}),
 		errs:               make(map[string]*plugins.SignatureError),
 		log:                &fakeLogger{},