[gnome-maps] (14 commits) ...Add README describing the transit plugin concept

[Marcus Lundblad <mlundblad src gnome org>]

Summary of changes:

  418e080... openTripPlanner: Move to a separate directory (*)
  1cb307d... openTripPlanner: Don't take GraphHopper instance as a param (*)
  b3c101d... openTripPlanner: Don't take query from params (*)
  6290418... Move common error messages to TransitPlan (*)
  fc49ce9... transitPlan: Add properties for attribution (*)
  bbb1b2a... transitPlan: Add error for no provider (*)
  3517dfa... utils: Add function to get current language (*)
  23acfef... photonGeocode: Use util function to get language (*)
  898dcbc... graphHopperGeocode: Use util function to get language (*)
  4cc11e1... Add transit router (*)
  d670a38... sidebar: Rename attribution link stack children (*)
  6bd09a0... sidebar: Update attribution (*)
  9da7837... sidebar: Update transit disclaimer (*)
  ad7793f... Add README describing the transit plugin concept (*)

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