Refactor forms with the Symfony Form component

[marien-probesys]

I started working on Bileto by creating forms manually. That was fine for some time, but I introduced the Form component to refactor the contract form. It removes a lot of issues (in particular, I no longer need to check the CSRF token manually).

Some forms would benefit of the same refactoring:

• new/edit contract
• new/edit organization
• new/edit role
• new/edit user
• new/edit mailbox
• new authorization
• new ticket
• all the edit forms related to the tickets
  • title
  • status
  • actors
  • priority
  • labels
  • contract
• answer ticket?
• profile
• preferences

This may take some time to refactor all the forms so I plan to refactor them slowly, at each release.