Remove storing of password in browser

Plaintext password was stored in localStorage. This was removed and replaced
by token.
Username is still stored -- we display it in the navigation bar.
Tests were updated to use only the token and a check for username in navbar
was added.

Change-Id: Id9a053e119f6826eda5472629f7d09e618297403
Implements: blueprint access-control-master-node-improvments
Merge "Remove storing of password in browser"