Add "Title" and "Blurb" to new profile editor

Summary:
Ref T1703.

  - Adds "Title".
  - Adds "Blurb".
  - Adds `user.fields` config for selecting and reordering. This will get UI in the next patch.

Test Plan:
{F45689}

{F45690}

Edited the fields, too.

Reviewers: chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T1703

Differential Revision: https://secure.phabricator.com/D6153