To do in branch decidim#0.12-stable
Since this feature won't be pushed to Decidim in BCN so far, it needs to be developed through extends(views being hard-coded)
To not forget to put the translations in all the yml language files !
FYI a similar feature has been discussed here but we won't take it into account in this dev so far
As an admin, I want to have to possibility to configure the process CTA button so that, depending on the step, I can ask the user for different kind of action.
So far the CTA button text is always "Participer":

What it should be:

For that, an admin needs to be able to configurate the process CTA button in Processes > [name-of-process] > Steps > [name-of-the-step]:
