Fix links in the headerbar
This adds the link to the index on the hubs-logo where it was
previously just #.
This also removes the links to nothing under user and email that
were in the user dropdown.
The only item in the user dropdown now is logout, and the font-awesome
signout icon is now next to the text.
Fixes: #438
Signed-off-by: Ryan Lerch <rlerch@redhat.com>