[MM-47542] Extend Plugin API (#21446)

* Extend Plugin API

* Use Error, NoError in tests

* Address suggestions

* Simplify code

* Add new line

* Add featureflag and GetCollectionMetadataByIds hook

* Add enter at the end of file

* make build-templates

* Fix test

* Fix GetCollectionMetadataByIds ret type

* Add GetTopicMetadataByIds hook

* Add log

* Extract i18n

* Add experimental notice on hooks

* Update model/feature_flags.go

* Swap user to userId

* Change userId to userID

Co-authored-by: Jesse Hallam <jesse.hallam@gmail.com>

app/plugin.go

@@ -486,6 +486,11 @@ func (a *App) DisablePlugin(id string) *model.AppError {
 }
 
 func (ch *Channels) disablePlugin(id string) *model.AppError {
+	for _, collectionType := range ch.collectionTypes[id] {
+		delete(ch.topicTypes, collectionType)
+	}
+	delete(ch.collectionTypes, id)
+
 	pluginsEnvironment := ch.GetPluginsEnvironment()
 	if pluginsEnvironment == nil {
 		return model.NewAppError("DisablePlugin", "app.plugin.disabled.app_error", nil, "", http.StatusNotImplemented)