Action to move PRs through project state

[james-bruten-mo]

This reusable workflow adds the ability to edit the Simulation Systems Review Tracker project.
Based on the reviewer entries in the PR template it will fill in the reviewer fields in the tracker.
Based on completed reviews by the SR and CR it will modify the project state.
It automatically adds the PR author as an assignee.
It will request a review from the CR if they are not already added.

To edit projects requires a PAT with project write access to be added as a secret to each calling repository. I propose we add a PAT to the umadmin account with that permission and use this as the secret for each repo.

There's a PR in the git_playground demonstrating it working https://github.com/MetOffice/git_playground/pull/112

We probably also want to check it works on the git_playground as a reusable workflow as well.

[james-bruten-mo]

I'm happy with the testing of this now - it's works from forks for all required triggers. Tagging @yaswant for a review for this going onto main

[yaswant]

We have done enough testing, and identified areas of improvements. I'm happy for this to go as an initial implementation.

[james-bruten-mo]

Thanks Yash, I've asked @jennyhickson to review the PRs adding the calling workflows, so passing this to her for CR too