Update git submodules
- Update extensions/CategoryTree from branch 'REL1_39' to fb9a5bfa2f4d052cc988093b88798592717134b3
- Localisation updates from https://translatewiki.net.
Change-Id: I892ea4478329a18a0f3f34b9a3d3f39751cc4e55
- Localisation updates from https://translatewiki.net.