GHA: Refactor repetitive action inputs into in-repo composite actions

[cognifloyd]

It has been difficult to keep some of the steps in our GHA workflows consistent with each other.

In investigating Microbenchmarks failures, I realized I missed updating one of the keys in #6192.

The cache actions have the most complex set of inputs, so I refactored them into composite actions that can be shared by all of the workflows. I'm loading these actions as local files (The ./ prefix is required for that), so the repo has to be checked out first before we can use actions like this.

Relevant Github docs: https://docs.github.com/en/actions/creating-actions/creating-a-composite-action https://docs.github.com/en/actions/creating-actions/metadata-syntax-for-github-actions#runsstepsuses https://github.com/orgs/community/discussions/26245