Move most Herald actions and values into dynamic adapters

Summary: Ref T2769. Shift the bulk of value and action config into Adapters.

Test Plan: Viewed and edited Herald list and rules.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran, vrana

Maniphest Tasks: T2769

Differential Revision: https://secure.phabricator.com/D6660