Investigate options for replacing 1 year secrets for GitHub Actions

[pjlewisuk]

Is your feature request related to a problem? Please describe.
Enterprise app secrets expire after 1 year, GitHub doesn't know when this is going to expire and so Actions just stop working when the secret expires.

We should investigate to see if there are any better alternatives to using Enterprise App Secrets.

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Describe alternatives you've considered
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[github-actions]

Issue smells stale, no activity for 30 days. Stale Label will be removed if the issue is updated, otherwise closed in a month.