Badges v0.1

Summary:
Basic plumbing for Badges application.

• You can make Badges.
• You can look at a list of them.
• They can be edited.
• They can be assigned to people.
• You can revoke them from people.
• You can subscribe to them.

Test Plan: Make Badges with various options. Give them to people. Take them away from people.

Reviewers: lpriestley, epriestley

Reviewed By: epriestley

Subscribers: tycho.tatitscheff, johnny-bit, epriestley, Korvin

Maniphest Tasks: T6526

Differential Revision: https://secure.phabricator.com/D13626