Get CI up and running again

[OllyK]

• Closes CI: Build runs not working as expected #18
• Adds a basic workflow to install package and run tests
• Adds a few tests
• Other CI actions still need to be disabled by maintainers using these instructions

[mb010]

A few questions on the tests and CI configuration. QOL improvements are amazing, and eventually we can be more specific with lower bound versions of packages.

[OllyK]

Hi @mb010 , do you want me to just delete the other failing GitHub workflows or are you happy to disable them for now?

[mb010]

Deleting them is fine. I'd rather have one system that works than a bunch that feel like they need to be maintained, when they're outdated. Happy to merge with the deletions done and the last update to the second test target shape made.

[mb010]

LGTM