R1:c6374e25d59c

Very rough edit workflow for AuthProvider configuration

Summary: Ref T1536. Many rough / broken edges, but adds the rough skeleton of the provider edit workflow.

Test Plan: {F46333}

Reviewers: btrahan

Reviewed By: btrahan

CC: aran, chad

Maniphest Tasks: T1536

Differential Revision: https://secure.phabricator.com/D6200