Loki: Decouple data source plugin (#107242)

* WIP

* Update yarn.lock

* Align uuid dependency

* Add e2e test and update

* Update cue version

* Fix lint

* Update snapshot test

* Fix test that was importing from coupled module

* Fix lint

* Update public/app/plugins/datasource/loki/package.json

Co-authored-by: Zoltán Bedi <zoltan.bedi@gmail.com>

---------

Co-authored-by: Zoltán Bedi <zoltan.bedi@gmail.com>

pkg/tsdb/loki/standalone/main.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"os"
+
+	"github.com/grafana/grafana-plugin-sdk-go/backend/datasource"
+	"github.com/grafana/grafana-plugin-sdk-go/backend/log"
+)
+
+func main() {
+	// Start listening to requests sent from Grafana. This call is blocking so
+	// it won't finish until Grafana shuts down the process or the plugin choose
+	// to exit by itself using os.Exit. Manage automatically manages life cycle
+	// of datasource instances. It accepts datasource instance factory as first
+	// argument. This factory will be automatically called on incoming request
+	// from Grafana to create different instances of SampleDatasource (per datasource
+	// ID). When datasource configuration changed Dispose method will be called and
+	// new datasource instance created using NewSampleDatasource factory.
+	if err := datasource.Manage("loki", NewDatasource, datasource.ManageOpts{}); err != nil {
+		log.DefaultLogger.Error(err.Error())
+		os.Exit(1)
+	}
+}