R1:a91a3cd22f18

Conpherence - refactor CSS a bit

Summary: Follow on to D12410. This kills the general CSS file that once powered application transaction in favor of a specific CSS file for the shared transaction styles for both full view and durable column view. I was able to delete some stuff and identify some shared stuff but there is probably more to go here. Also, rename "phabricator-x" to "conpherence-x" for class names.

Test Plan: viewed full conpherence and durable column conpherence and things looked nice…