Client connection states

[Allen-Glass]

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] All new classes have class-level documentation comments, if there are any at all
• [x] Tests for the changes have been added (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Build related changes
• [ ] CI related changes
• [ ] Documentation update
• [ ] Other... Please describe:

What is the current behaviour?

We have no way to track a client's connection state to the coop server

What is the new behaviour?

A way to track each client's connection state within the coop server. Resolves # #289 Added a simple event listener to track where a client is at when connected to the coop server. Building block for more complicated server connection state behavior

Other information