Plugins: Introduce plugin asset provider (#108063)

* introduce plugin asset provider

* simply with PR feedback

* fix linter

pkg/plugins/pluginassets/pluginassets.go

@@ -0,0 +1,28 @@
+package pluginassets
+
+import (
+	"path"
+	"path/filepath"
+
+	"github.com/grafana/grafana/pkg/plugins"
+)
+
+var _ Provider = (*LocalProvider)(nil)
+
+type LocalProvider struct{}
+
+func ProvideService() *LocalProvider {
+	return &LocalProvider{}
+}
+
+func (s *LocalProvider) Module(plugin PluginInfo) (string, error) {
+	if plugin.Class == plugins.ClassCore && filepath.Base(plugin.FS.Base()) != "dist" {
+		return path.Join("core:plugin", filepath.Base(plugin.FS.Base())), nil
+	}
+
+	return s.AssetPath(plugin, "module.js")
+}
+
+func (s *LocalProvider) AssetPath(plugin PluginInfo, assetPath ...string) (string, error) {
+	return path.Join("public/plugins", plugin.JsonData.ID, path.Join(assetPath...)), nil
+}