Add multilingual support

Added initial support, but it's not tested yet with non-multilingual sites and requires more work. This is just a first draft that will be extended.

bbu23 → changed the visibility of the branch 3347964-multilingual-support-v2 to hidden.

It's definitely not perfect, but I've been running this for a while now, and so far so good. Haven't had any problems on a multisite/multilingual setup. If anyone discovers any bugs, feel free to open a new issue.

Automatically closed - issue fixed for 2 weeks with no activity.