trivial: Set the IdKind in the self test program
Set the GsAppIdKind for applications installed locally without AppStream metadata.
Show 'Add-ons' in a seporate group on the installed shell

Resolves: https://bugzilla.gnome.org/show_bug.cgi?id=709562
Split out an 'Add-on' group in the updates shell

Resolves the other half of: https://bugzilla.gnome.org/show_bug.cgi?id=709562