refactor: replace SubscriberBus usage in favor of event driven websocket emits

[mvdicarlo]

A massive refactor that overhauls how we internally calculate websocket emits to make
emissions more granular and not require emitting every single record over the wire
whenever a single change is made.

To support this, lot of changes were required to be made around submission emissions
and a relatively large restructuring of login lifecycle ownership for accounts. Ownership
of login state is largely now managed by website instances themselves.

This is likely to have buried bugs and needs some general refinements but is overall
stable from initial testing.