R1:87d360bb1b4a

Conpherence - refactor display classes a bit

Summary:
D12409 made me realize this was a bit janky. `PhabricatorTransactionView` was only being used by Conpherence, so move and rename that class to `ConpherenceTransactionView`. Also, rename the existing `ConpherenceTransactionView` to `ConpherenceTransactionRenderer`, moving the actual view bits into the new `ConpherenceTransactionView`. Resulting code is a bit cleaner IMO.

Diff 1 of 2 (second diff has to be written. =D). Diff 2 will take care of the CSS…