R1:a035d3d528b2

Remove PhabricatorProjectEditor

Summary:
Ref T4379. Perform all editing with modern transaction infrastructure. A few practical changes here:

- Message for "project name required" should be a little nicer. I'll deal with this once more stuff gets straightened out. You get a reasonable message now, it's just not nicely handled as part of the form.
- Message for "project name is not unique" should be a little nicer. Same as above.
- Previously, we would automatically archive a project when the last…