Update git submodules
- Update extensions/Gadgets from branch 'REL1_39' to 5040a642d7f4b9c9486c0e9445cc4f43468bf7e4
- Localisation updates from https://translatewiki.net.
Change-Id: If19b52a8cd6641b8a6134b303b479c18a8648f24
- Localisation updates from https://translatewiki.net.