i18n update for Occitan language (#3362)

* Update simple_form.oc.yml

* Added check spam folder

* Update oc.json

abonats => seguidors

* Update oc.yml

* Update oc.json

Added translations + corrections

* Update confirmation_instructions.oc.html.erb

* Update confirmation_instructions.oc.text.erb

* i18n mailer

* Update reset_password_instructions.oc.html.erb