R1:349a8c60e8a9

Phriction handles and search

Summary: Index Phriction documents in search, and allow
PhabricatorObjectHandleData to load them.
Test Plan: Searched for "pokemons", got my wiki page as a search result.
Reviewed By: hsb
Reviewers: hsb, codeblock, jungejason, tuomaspelkonen, aran
CC: aran, hsb
Differential Revision: 648