Consider identifier types when sorting clone URIs

Summary:
Fixes T11082. Currently, the /123/ and /CALLSIGN/ versions of the URI get the same score.

Also the scores are backwards.

Test Plan:

• Added getPublicCloneURI() output to repository listing.
• Before patch, saw a repository with a callsign list a less-preferred ID-based URI.
• After patch, saw the repository list the more-preferred callsign-based URI.

Reviewers: chad

Reviewed By: chad

Subscribers: nikolay.metchev

Maniphest Tasks: T11082

Differential Revision: https://secure.phabricator.com/D16008