R1:663dce5029f5

Flesh out Conduit parameter types for Owners + CustomFields

Summary:
Ref T9964. Fill in more parameter types and descriptions.

(No date support yet since it's a bit more involved.)

Test Plan: {F1024022}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9964

Differential Revision: https://secure.phabricator.com/D14766