Add Yoruba language to l.d.o

+1 to moving this forward. I know only a few words of Yoruba (from studying some of the sacred music culture in Brasil), so I'd be very little help on the translation itself, but I'd be happy to be involved in a translation group if that's useful. I'm https://localize.drupal.org/user/14 over there.

Thanks!
-Derek

(sorry for the noise, trying to fix the issue tags)

Wow, I can't seem to get Nigeria back to capitalized. I'm going to clear out the tags, they're not needed...

Sorry/thanks,
-Derek

https://docs.translatehouse.org/projects/localization-guide/en/latest/l1... includes the plural forms for Yoruba, added to the summary.