[gnome-characters] (15 commits) ...Merge branch 'bilelmoussaoui/ui-cleanup' into 'master'

[Christopher Davis <christopherdavis src gnome org>]

Summary of changes:

  9dc90d6... misc: add a .gitignore (*)
  b813545... flatpak: remove unneeded options (*)
  e1ee859... flatpak: add migration (*)
  a7a12a1... window: use HdyApplicationWindow (*)
  4968e55... window: split header bars (*)
  1c52e32... sidebar: remove the use of a sub-categories for now (*)
  8e1281b... make use of HdyStatusPage (*)
  1459420... sidebar: finish the recent items changes (*)
  a6c985b... split the menu into primary & secondary (*)
  275aac3... CI: add libhandy1 (*)
  33f13d8... sidebar: load icons as symbolics (*)
  4d30c4f... window: remove pre-specified css classes (*)
  4126a36... window: wrap back button in a reavealer (*)
  46930bd... build: use a subproject as a fallback for libhandy (*)
  6ec1413... Merge branch 'bilelmoussaoui/ui-cleanup' into 'master'

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