Move most Herald condition config into dynamic adapters

Summary: Ref T2769. Pushes most condition configuration into Adapters, out of the hard-coded class.

Test Plan: Looked at, edited, and dry-run'd Herald rules.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2769

Differential Revision: https://secure.phabricator.com/D6658