Localisation updates from http://translatewiki.net.

Change-Id: Idf313abdb347b6b273822b6df931b8b9e68a8aa0
Add getKeys optimization to BannerMessageGroup

This avoids the wfMessage calls to load message content.

Bug: 53769
Bug: 53792
Change-Id: I14cdda777e3a70cda78d2f52d59b6ad569619571
Localisation updates from http://translatewiki.net.

Change-Id: Iab56fabe8ca291e3df04e5f843b0746664c8460f
Merge branch 'master' into wmf_deploy

* master:
  Localisation updates from http://translatewiki.net.
  Add getKeys optimization to BannerMessageGroup
  Localisation updates from http://translatewiki.net.

Change-Id: I2b158e845168a63ee4a35b78eb87ce53fb427cb0