Implemented automation workflows for change notes and release building

[DC23]

I've implemented two release automation workflows.

1. Release Drafter, which creates release notes from PR names and PR labels. The Release notes template is .github/release-drafter.yml. In the categories section you will see the mapping between labels and categories. I've used the categories I use on my other project. You can change these to suit. You don't have all the labels yet. Add what you need, adjust categories and it will all work. Note that a PR should only have a single label, or it gets added to the release notes twice.

If you change the PR label or title later, the workflow can be run manually and it will update the notes while they are still in draft.

2. Release Creation: this one fills in the tags in the system.json, builds the zip, and publishes the new release. It doesn't update Foundry, I haven't sorted that part out yet.

For both, I have the workflows running with the minimum permissions possible, so you can reduce the default Actions workflow permissions from the default "read and write" to "read".

These two PRs should have no overlapping files, but you probably still want to merge this one first.

[DC23]

I updated the PR title. It's an example of the type of title that works really well with the release drafter workflow. The title is a single active sentence that describes to a reader the key change that the PR implemented. It will automatically show up in the release notes, categorised by whatever label you add to the PR.