Support searching for Related Commits by package owner

Summary:
add support for searching by package owner for Related Commits
and commits that Need Attention.

Test Plan:
verified that

• searching by package still works when there is or there is no commits found
• searching by package owner works when there is or there is no commits found

Reviewers: epriestley, nh

Reviewed By: epriestley

CC: aran, epriestley, prithvi, dihde14, Girish

Differential Revision: https://secure.phabricator.com/D1631