Rename BKE_appdir_folder_id_version to
BKE_appdir_resource_path_id_with_version because BKE_appdir_folder_id
and BKE_appdir_folder_id_version didn't accept compatible arguments.
Also add notes to GHOST_getSystemDir & GHOST_getUserDir that
BKE_appdir_resource_path_id(..) should be used instead (in most cases).