Adds support for Firefox

Also create seperate account security options page

This commit requires a new database table

These features only have any value if users actually use them, and
experience has shown that nowhere near enough users use them to make
them worthwhile.

- Removed unused JS functions
- Inlined functions not often used
- Minimized some overly verbose functions

Also file permission cleanup

2FA class stolen from RobThree and stripped down.
Works best with qrencode utility installed, but will fall back to using
google charts if qrencode is missing.