Real-time evaluation step status updates for client

[HenningCash]

📢 Type of change

• New feature (non-breaking change which adds functionality)

📜 Description

Because evaluation steps are now run in parallel we can give the user immediate feedback if the step has finished. This PR pushes the new status to the client.

I used this to refactor a lot of client-side code (and some of the subscription API):

• To watch an evaluation for an answer there is now a single subscription evaluationStatusUpdated that will push changes either for all evaluations of a user or for a single answer.
• I moved A LOT of components from the EvaluationResult page to their own component
• GraphQL fragments now have their own directory

🔗 Related Issues

• Fixes # (issue)

☑️ Checklist:

• I have performed a self-review of my own code
• I have run the auto code formatting scripts
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I updated the CHANGELOG.md
• I have added tests that prove my fix is effective or that my feature works