[gnome-maps] (9 commits) ...layersPopover: Show dark street thumbnail when night mode active

[Marcus Lundblad <mlundblad src gnome org>]

Summary of changes:

  70e7597... gschema: Add night-mode schema key (*)
  575e47f... utils: Add ability to create actions mapped to a GSettings  (*)
  e0a02d0... application: Add action for toggling night mode (*)
  371655c... mainWindow: Add item to main menu to toggle night mode (*)
  e21aac3... maps-service: Add dark street tile definition for fallback (*)
  cc2f76f... mapSource: Add function to create dark source (*)
  3662429... mapView: Use dark tiles when night mode is active (*)
  116becd... mapView: Set a dark view background when in dark theme mode (*)
  7580add... layersPopover: Show dark street thumbnail when night mode a (*)

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