Completed Paste Generation

Summary: Ref T2903

Test Plan: Pastes being generated with all types of parents, view policies, code, etc.

Reviewers: epriestley, AnhNhan

Reviewed By: epriestley

CC: AnhNhan, aran, Korvin

Maniphest Tasks: T2903

Differential Revision: https://secure.phabricator.com/D5707