Summary:
Ref T603. Ref T2625.

Long chain of "doing the right thing" here: I want to clean this up, so I can clean up the Conduit logs, so I can add a setup issue for deprecated method calls, so I can remove deprecated methods, so I can get rid of `DifferentialRevisionListData`, so I can make Differntial policy-aware.

Adds modern infrastructure and UI to all of the Conduit interfaces (except only partially for the logs, that will be the next diff).

Test Plan:
{F48201}
{F48202}
{F48203}
{F48204}
{F48206}

This will get further updates in the next diff:

{F48205}

Reviewers: btrahan, chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T603, T2625

Differential Revision: https://secure.phabricator.com/D6331