R1:b199f7066c9c

Conpherence - add support for linking directly to messages regardless of age of message

Summary: Fixes T7757. Since anchor links can't be processed server side, we have to detect the message is old in javascript, then re-loaded the page. This opens up a new corner case where we have to paginate in newer messages, so this also adds support for that.

Test Plan:
- set main query limit to 8 and then visited ZXX#YYY. noted a second quick load of YYY, that YYY ended up highlighted and scrolled to.
- used "show…