[polari] (11 commits) Non-fast-forward update to branch wip/fmuellner/cleanups

[Gitlab Administrative User <gitlab src gnome org>]

The branch 'wip/fmuellner/cleanups' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  e09370a... cleanup: Use Array.includes() to check for element existenc
  6774bac... cleanup: Replace more plain objects with Maps
  f6f635f... cleanup: Use class methods for singleton pattern
  6f1867c... cleanup: Use class getters instead of globals

Commits added to the branch:

  9181031... build: Update appdata install path (*)
  a27df7e... build: Remove autotools left-over (*)
  228d81a... build: Include prefix in libdir & co. (*)
  d546070... cleanup: Use Array.includes() to check for element existenc
  caa067a... cleanup: Replace more plain objects with Maps
  8abb0ed... cleanups: Remove unused imports
  e8d14c6... cleanup: Regroup imports
  7501530... cleanup: Import classes directly where it makes sense
  0ab064a... cleanup: Make singleton classes public
  ad43c20... cleanup: Use class methods for singleton pattern
  e611aa3... cleanup: Use class getters instead of globals

(*) This commit already existed in another branch; no separate mail sent