Use Adapters to render Herald transcripts

Summary: Ref T2769. Use Adapters to build all the strings for transcripts, then get rid of the old maps.

Test Plan: Viewed revision and commit transcripts.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2769

Differential Revision: https://secure.phabricator.com/D6663