Update git submodules
- Update extensions/MultimediaViewer from branch 'REL1_42' to 70bbe16cb1ed0151a4039f9b2f75dc07f8589632
- Localisation updates from https://translatewiki.net.
Change-Id: Ic9d661f53ea6bfae4a58b8e104a9286832065a5a
- Localisation updates from https://translatewiki.net.