Add fix for welsh sign in and register buttons
Merge pull request #527 from moneyadviceservice/welsh_auth

Add fix for welsh sign in and register buttons
Add Feedback entity.
Setup ActionMailer.
Add a basic feedback repository with a private mailer.
Add a FeedbackWriter interactor.
Add dough.
Refactor feedback entities to cover different types of feedback.
Implement feedback page for articles.
Implement general (technical) feedback page.
Implement the money advice page.
Add links to give feedback to the article show page.
Put the feedback panel on articles behind a feature toggle.