Sync with the OBS for correct version numbers

The package name will now include the git hash, and Trojita will report itself
using format very similar to what the git builds do. The -git- is replaced by
-obs- to make it clear where it comes from; the idea is that this will make it
easier to diagnose where the bug reports are coming from.
Ubuntu remove unused icons from MessageListPage.

There is no need to have a performance hit by drawing these two icons
for every delegate if they do nothing or a planned to do nothing

REVIEW: 118095