Update git submodules
- Update extensions/Gadgets from branch 'REL1_40' to e2644cfbdf40dacf2cd6bfdb95ecda31fe7eca57
- Localisation updates from https://translatewiki.net.
Change-Id: I7cbc0c2ee4cab3cc0dda37fe3819fe9ef5fde9c6
- Localisation updates from https://translatewiki.net.