Plugins: Refactor Grafana and Plugin version update checkers (#44529)

* refactor

* rework plugin update checking

* make smarter

* simplify

* fix linter issue

* make use of mutex

* apply feedback to simplify

* format imports

* fix tests

pkg/server/wire.go

@@ -109,7 +109,8 @@ var wireBasicSet = wire.NewSet(
 	hooks.ProvideService,
 	kvstore.ProvideService,
 	localcache.ProvideService,
-	updatechecker.ProvideService,
+	updatechecker.ProvideGrafanaService,
+	updatechecker.ProvidePluginsService,
 	uss.ProvideService,
 	wire.Bind(new(usagestats.Service), new(*uss.UsageStats)),
 	manager.ProvideService,