Add Occitan (oc) translation (#2077)

* Added oc.yml

* Added `config/locales/oc.yml`.
  Translated in General Occitan (Quent-in).

* Added oc.jsx (Occitan translation)

* Written in General Occitan (lengadocian)
* Added `app/assets/javascripts/components/locales/oc.js`

* Added doorkeeper.oc.yml

* Added `config/locales/doorkeeper.oc.yml` (Quent-in)

* Added simple_form.oc.yml

* Added `config/locales/simple_form.oc.yml` (Quent-in).

* Merge en.yml changes into oc.yml

Added new strings for translations

* Fix typo in oc.yml

* Update javascript locale support (oc)

* Update ruby locale list (oc)

* Fix oc.yml

* Remove obsoleted translations
* Moved old translation of `reports` to `admin.reports`