Remove needRecipients and needAwards from Badges

Summary: Fixes T10798. Separates these two since they don't need to be combined and it allows for more flexibility / scalability.

Test Plan:

• Add Badge
• Edit Badge
• Add myself as Recipient
• Remove myself
• Go to my profile
• Award Badge from there
• Assign myself a badge, try to re-assign it, see validation error.

Also, validation errors on dialog forms are ugly.

{F3495630}

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T10798, T12270

Differential Revision: https://secure.phabricator.com/D17447