Mask remaining config values, and implement set type
Summary: The remaining hash/key values are already-migrated, I am just bad at grep. Also implement a "set" type.
Test Plan: Looked at set, edited set.
Reviewers: codeblock, btrahan
Reviewed By: codeblock
CC: aran
Maniphest Tasks: T2255
Differential Revision: https://secure.phabricator.com/D4476