Assorted cleanups
Some stuff that doesn't fit elsewhere:
* main: Allow F11 as fullscreen shortcut
* metainfo: Remove .desktop from app-id
As per https://freedesktop.org/software/appstream it's not part
of the app-id.
Some stuff that doesn't fit elsewhere:
* main: Allow F11 as fullscreen shortcut
* metainfo: Remove .desktop from app-id
As per https://freedesktop.org/software/appstream it's not part
of the app-id.