🛠️ [TASK] : Make github action/s which can pre populate and validate Project fields in PRs and Issues

[stevenj]

Summary

We want to make sure project fields are completed before tickets are close DONE, or PRs are merged.

Description

The following are fields which we want completed for all Tickets closed as Done, and all PRs that are merged:

In order to improve project tracking, it would be good to have the following automated:

1. Auto assign PRs to the author. See: https://github.com/marketplace/actions/auto-author-assign
2. Auto select the next milestone, when a PR or Issue is created. See: https://github.com/benelan/milestone-action
3. If possible, default Project Fields. to sensible defaults. Priority Medium, and for a PR, set the iteration to the current one, and start date to today.
4. Before a PR can be merged, all fields need to be filled in.
5. Before a ticket is closed as DONE, all fields need to be filled in.

There are github actions which may help with some of this, or it may require custom actions to be written.
The aim is to streamline Ticket and PR creation and ensure all fields are reliably completed all the time.

This may require multiple actions.
The actions should be made in cat-ci, and referenced from our other repos to maintain uniformity of implementation and simplify maintenance.