Rearrange the pages and settings in "My Account".

Review Request #770 — Created July 18, 2017 and updated — Latest diff uploaded

Review Board
The various knobs and gewgaws in the account settings had grown organically,
and were kind of a big mess. We had things spread around too many pages and in
somewhat random order.

This change rearranges things so that the user profile information comes first
(name, e-mail address, avatar, etc). Next is settings, which includes general
settings and notifications. Groups is moved to be third on the list (instead of
first), and finally the authentication page has the password and API tokens

Testing done:
- Ran unit tests.
- Verified that loading and saving all of the various settings worked correctly.

Reviewed at