judging: implement judging phases

This MR unifies different controls into a single table for determining which Judging Phases the competition is at. Moving it to a single service will simplify multiple implementations (currently using feature flags, KVS, entities), and also assert the system evolves in a safe manner (e.g., we cannot start voting before the assignments have been made).

This is a pre-work in order to implement the Ratification sub-module.

BE for websites/root!755 (merged)

Summary by CodeRabbit

• New Features

  • Introduced functionality to manage judging phases for competitions, including checking status, retrieving details, and handling phase transitions.
  • Enhanced competition creation to include author details and event emission.

• Bug Fixes

  • Improved error messages for competition status assertions.

• Tests

  • Added testing for judging phase functionalities, including assertions for phase status and handling commands like opening and closing phases.