Provide a way to delete broken apps

[FredM67]

Currently, if an app is broken, the user needs to get the list of the apps ".../app/list", then type an url with "remove?..." as described in https://community.openenergymonitor.org/t/cant-delete-app/6036.

Please provide a UI to both get the list of the apps AND delete it, somehow similar as the UI for bookmarks (.../emoncms/user/bookmarks). Should be possible to reuse this UI to minimize the effort.