Plug-ins i18n via Transifex

[nhl.pl]

Some interesting feature requests can be found here:
https://github.com/NodeBB/nodebb-plugin-2factor/pull/93

In short:

• proposal to move all language files to Transifex and allow translators to work on translating plug-ins (pre-installed/default/bundled plug-ins were mentioned),
• 123456 vs. 123 456 as common i18n problem not only for Korea and Japan,
• some other shortcomings from Korean user point of view.

https://github.com/NodeBB/nodebb-plugin-2factor/pull/93