Replace usage of SpecialPage::getTitle with getPageTitle

Was deprecated in 1.23, see Icdcf5d5295ef5e7f08b1d403e0c123f78738fd40

Change-Id: Ic93acec97ebfa64ea51d9f80b1cff83296248f91
Migrate to JSON i18n

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

Change-Id: Ia62e0e3eea4bfa4d47e1fdd96133eb2f7e08be90
Remove zh-[cn|tw] in favour of zh-han[s|t]

Change-Id: Ifb92c4e4a7fb96a394758cbc0539a1949bdc0a62