Move people list rendering into SearchEngine

Summary:
Ref T4986. One note:

• We have a separate "browse directory" capability, to provide some soft privacy for users of public installs. Respect that policy within the SearchEngine.
• Also restore some other icons I missed earlier.

Test Plan:

• Viewed people list.
• Build people panel.
• Verified people panel was just me without browse capability.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T4986

Differential Revision: https://secure.phabricator.com/D9137