Plugins: Use grafana-plugin-sdk-go v0.5.0 (#21116)

* fix dispense

* plugin loading refactor

Moves common functionality of registering, starting,
stopping and restarting backend plugins to
backendplugin package.

* simplify plugin descriptors

* target sdk v0.5.0

Co-authored-by: Kyle Brandt <kyle@kbrandt.com>

pkg/services/rendering/rendering.go

@@ -7,9 +7,6 @@ import (
 	"os"
 	"path/filepath"
 
-	plugin "github.com/hashicorp/go-plugin"
-
-	pluginModel "github.com/grafana/grafana-plugin-model/go/renderer"
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/middleware"
 	"github.com/grafana/grafana/pkg/models"
@@ -25,8 +22,6 @@ func init() {
 
 type RenderingService struct {
 	log             log.Logger
-	pluginClient    *plugin.Client
-	grpcPlugin      pluginModel.RendererPlugin
 	pluginInfo      *plugins.RendererPlugin
 	renderAction    renderFunc
 	domain          string
@@ -85,15 +80,8 @@ func (rs *RenderingService) Run(ctx context.Context) error {
 	}
 
 	rs.renderAction = rs.renderViaPlugin
-
-	err := rs.watchAndRestartPlugin(ctx)
-
-	if rs.pluginClient != nil {
-		rs.log.Debug("Killing renderer plugin process")
-		rs.pluginClient.Kill()
-	}
-
-	return err
+	<-ctx.Done()
+	return nil
 }
 
 func (rs *RenderingService) RenderErrorImage(err error) (*RenderResult, error) {