R1:4d362ddcee4a

Ref T6049, Add Phurl URL create capability

Summary: Ref T6049, Add Phurl URL create capability

Test Plan:
- Change {nav Home > Applications > Phurl > Configure} to allow no one to create Phurl URLs
- Attempt {nav Phurl > Shorten URL}. Should not be able to create a Phurl.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin

Maniphest Tasks: T6049

Differential Revision: https://secure.phabricator.com/D14510