[API][v1] Extract common functionality from account, events, state modules

[banool]

Currently there is a bit of code duplication and some nasty coupling between these different components, where events is something of an extension on top of accounts. As such, much of the events specific code is in the file for the accounts component. The state section of the API also duplicates some stuff we do in the other API components.

This code could be cleaned up pretty easily, but it's not very high pri right now.