New UI for fulltext message search

Summary: Basically all here, but still probably needs some polish (links to jump? full dates?). Looks much better, still duplicates messages though sometimes. Needs to debug that more.

Test Plan:
Revisit search UI inside Conpherence, outside Conpherence, and normal room searches in Conpherence.

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Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D16708