Plugins: Refactor loader + finder to support multiple sourcing methods (#64735)

* it's cdn time

* tidy body closing

* auto signed

* fix close

* update log name

* remove comments

pkg/plugins/manager/loader/ifaces.go

@@ -9,7 +9,7 @@ import (
 // Service is responsible for loading plugins from the file system.
 type Service interface {
 	// Load will return a list of plugins found in the provided file system paths.
-	Load(ctx context.Context, class plugins.Class, paths []string) ([]*plugins.Plugin, error)
+	Load(ctx context.Context, src plugins.PluginSource) ([]*plugins.Plugin, error)
 	// Unload will unload a specified plugin from the file system.
 	Unload(ctx context.Context, pluginID string) error
 }