[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_api.go

@@ -1231,3 +1231,9 @@ func (api *PluginAPI) GetCloudLimits() (*model.ProductLimits, error) {
 	limits, err := api.app.Cloud().GetCloudLimits("")
 	return limits, err
 }
+
+// RegisterCollectionAndTopic informs the server that this plugin handles
+// the given collection and topic types.
+func (api *PluginAPI) RegisterCollectionAndTopic(collectionType, topicType string) error {
+	return api.app.registerCollectionAndTopic(api.id, collectionType, topicType)
+}