Update git submodules
- Update extensions/PdfHandler from branch 'REL1_40' to 5743082cbcf4ae61300ae7a3fb4b6ecbf6d729e6
- Localisation updates from https://translatewiki.net.
Change-Id: Ib1e09486f0f9a52971f0531fd49714969e71bec4
- Localisation updates from https://translatewiki.net.