[FA-11] Adding endpoint for challenging real person

[scott-clare1]

This PR adds an endpoint for creating a game against a real user and checking whether it is the agents turn or not

I have also added an exceptions module for informative exceptions for the agent.

Checklist

Please ensure you have done the following:

• I have read the CONTRIBUTING guide.
• I have updated the documentation if required.
• I have added tests which cover my changes.

Type of change

Tick all those that apply:

• Bug Fix (non-breaking change, fixing an issue)
• New feature (non-breaking change to add functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Other (add details above)

MacOS tests

To trigger the CI to run on a macOS backed workflow, add the macos-ci-test label to the pull request (PR).

Our advice is to only run this workflow when testing the compatability between operating systems for a change that you've made, e.g., adding a new dependency to the virtual environment.

Note: This can take up to 5 minutes to run. This workflow costs x10 more than a Linux-based workflow, use at discretion.

[samgwd]

Given we will be open sourcing this, lets try get into a good habit for PR summaries. Can you make sure we've been through the checklist and ticked the boxes. One thing I've used before in PR summaries is a template of 'What', 'Why', 'How', 'Extra'. Each as titles. Let me know what you think for this.