Branch and tag protection rules

[hairmare]

As part of an automated build-pipeline, the main branch and all important tags need protecting. There is currently this warning on the repo:

This can be configured here: https://github.com/radiorabe/actions/settings/rules

Setting this up is simple

1. Configure default rulesets as "Disabled" so they can be reviewed prior to being enabled
2. Enable the rules

We need to be sure that the rules don't conflict with the activity on the repo, this could imply switching to a pull request based model before enabling branch protection.