BUG8446, Follow up: Improve local login fallback

- Local fallback was not very well implimented, this patch adds
  better handling for such cases allowing clearer failure messages
- This patch also adds the ability to use single sign on via the
  top bar menu in the bootstrap theme.

BUG8446, Follow up: Adds perldoc documentation

- Add some documentation to the Auth_with_Shibboleth module
  including some guidance as to configuration.
BUG8446, Follow up: Correct filenames to match guidlines

- Moved Auth_with_Shibboleth.pm to Auth_with_shibboleth.pm to match
  other files present on the system.
BUG8446, Follow up: Correct paths after file rename