Update _tenancy.html.haml

- added demoted tenancy fields to bottom of this section
- removed grey info box from top
- moved 'date' of first tenancy agreement into white box
- moved 'If you've had more than one tenancy...' into the white box
- added line copy before the 2 radio button questions 'same property','same landlord/tenant'
- updated copy on dropdowns and radio buttons