Improved appsmanagement

This adds several improvements to the apps management. If a user disables an 3rd party app the app is completely removed so that a possible new version is downloaded and installed if enabled again. There is an "update" button on the apps page if a new version is available. The app is updated on click. It also introduces a new "recommended" app label that we use for apps that are stable and well tested. Several smaller improvements and fixes are also added.