Update git submodules
- Update extensions/MultimediaViewer from branch 'REL1_41' to 77c664e03af65d26837f761dd9878ed7686683c4
- Localisation updates from https://translatewiki.net.
Change-Id: Ia09947593f9289d4e037bb2b3349dabb02d06cf2
- Localisation updates from https://translatewiki.net.