[feat] Improve CI

Improve CI across all repos, including things like:

• [ ] - Consider using container jobs
• [x] - Use arm64 hosted runners -> https://github.com/open-space-collective/open-space-toolkit/pull/176
• [ ] - Minimise double-builds between test and production
• [ ] - Minimise building 3rd-party dependencies from source
• [ ] - Check that docker cache is being utilised fully
• [ ] - ABI checking
• [ ] - Reusing CMake build cache between jobs
• [ ] - use mypy against python tests to check stub syntax
• [ ] - package artifacts in merge-to-main pipelines aren't being reused in release CI?
• [ ] - run benchmark & validate step in PR CI
• [ ] - Add auto-releasing by including [tag] in the MR name