- make repo use jobs as a pipeline

[JC-DSIT]

Proposed changes

What changed

GitHub actions have been set to run on workflow call rather than push
single CI/CD job set up to use the steps as a pipeline

Related issue or tracking reference

no issue, just a minor tech debt update

Checklist

Before you request approval you should confirm that:

• the pull request has a clear title with a short description about the update in the documentation
• GitHub actions all pass
• you have tested the changes with a fresh build against the latest version of the tech-docs-gem
• you have linked this PR to an issue (or explained why none exists)
• you have updated documentation if needed