audit_log: massive refactoring and cleanup

i'm gay now

• tweak method names of AuditLog
  • self._send_task_func -> self._sender
  • likewise, self._send_task -> self._sender_task
  • _actual_send -> _consume_and_process_queue
    • uses copy.copy now
• removed request['_ctx_admin_id'] because we can use the id from request['ctx']
• Action changes
  • renamed _id, _object, _before, _after, _get_object to remove leading _ for clearer code (is arguable)
  • renamed _obj to object in DeleteAction
  • renamed action.insert to action.update, directly use self.context.update
    • also refactored user code to take advantage of multiple kwargs instead of calling update() multiple times
    • reflects dict.update
  • renamed _text to details: this makes it more clear that the stuff returned from this method will be the details of the action
  • removed _ctx in favor of having __getattr__: action['stuff'] instead of action._ctx('stuff') is better and semantically makes more sense (same behavior though)
  • renamed full_text to render: a bit shorter while still meaning the same thing
  • merge all text rendering methods into render: i think that splitting them up into methods was unnecessary in this situation imo (code flow as kinda complicated for a method that only has a few branches)
  • also impl __contains__ for in operator to check if stuff is present in self.context (unused atm, but can be useful in the future)
  • diff_keys renamed to different_keys and no longer @property
    • no longer being a property is arguable, but i removed it because it's kinda performs a calculation so it would be clearer to say that by forcing the user to put ()
  • iter_diff_keys renamed to different_keys_items and no longer @property
    • iter_ prefix is kinda 👎 imo
    • _items kinda goes hand in hand with dict.items() since this function yields keys and values just like dict.items()
• renamed all __Ctx actions to __Action (e.g. UserEditCtx -> UserEditAction)
  • more consistent with the existing "Action" naming scheme
  • creates a more consistent naming scheme for telling the person reading the code "this will push to the audit log queue"
• renamed DomainBroadcastCtx to DomainOwnerNotifyAction
  • name is better imo, "DomainBroadcast" might imply that something is broadcast to all user of that domain