Update Form Templates

- Remove grid <div> tags
- Add <fieldset> + <legend> tags
- Add a missing <section> tag
- Set responsive <form> display (i.e. grid classes)
Add Browser Feedback to Bug Tracker

- Add simple navigator/window infos to returned bug

N.B: alert-box has to be templated
Edit Footer

- Remove Mentions légales from sitenav
- Add dummy policy links to end notes
Update main CSS file

- Edit end notes style
- Correct alert-box styles
Update Login

- Change form id name and referer
- Delete a blank line