WIP: Feature/signup

TODO:
- [x] Put CSRF token to DOM so it is compilable with Flask-wtf-csrf
- [x] Setup mandrill credentials to production environment
- [x] Set default email sender
- [x] Set email copy
- [ ] Tests to email service
- [x] Correct domain to activation links

Define a server_default also as `server_default='FALSE'` (in Pelsu adding server_default is not needed since it uses SQLAlchemy-Defaults).