RequestContext has existed since 1.18, and getNamespace() since forever

Change-Id: I7a0318d9120a45d4b873d21c5ec322ae3d0fcc5b
Localisation updates from https://translatewiki.net.

Change-Id: I26f4f135ee4dda56765dcb2156a472ba61d88553
Localisation updates from https://translatewiki.net.

Change-Id: Ieeaccbb6aca92bcf7b24856026af14663e412aab
Added fix Uckelman - NS detection

Change-Id: Ibd8be81780c44407bb20abc4d0ef4ae420fe5eec
Migrate to JSON i18n

Procedure per https://www.mediawiki.org/wiki/Manual:GenerateJsonI18n.php
with shim.

Change-Id: Ie0de186e7559025aafd13e31d463f095bdf9a70d