* migrate to new manifest format
* rename app to alerting.notifications to not conflict with rules
* disable custom field selectors as they are not supported in appinstaller
* introduce alerting notification app
* move code as is and remove from old registry
* update api server registration
* update make file and remove unnecessary args, copy some useful make commands from dashboards
* update codeowners
* move constants inside module and remove dependency from grafana
* add support for selectors to the app builder