Update git submodules
- Update extensions/MultimediaViewer from branch 'REL1_43' to aa425b40ca0e8c1031f1b7077caa13197c211d3d
- Localisation updates from https://translatewiki.net.
Change-Id: Ifced1fc6429eb0ce0e5d99c8c839ea13110a645f
- Localisation updates from https://translatewiki.net.