Add cron jobs to helm chart to purge and rotate secrets

[JAORMX]

Summary

This adds jobs so we can purge sessions and rotate provider secrets in
an automated fashion.

Related-To: #3315

Change Type

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• Bug fix (resolves an issue without affecting existing features)
• Feature (adds new functionality without breaking changes)
• Breaking change (may impact existing functionalities or require documentation updates)
• Documentation (updates or additions to documentation)
• Refactoring or test improvements (no bug fixes or new functionality)

Testing

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Review Checklist:

• Reviewed my own code for quality and clarity.
• Added comments to complex or tricky code sections.
• Updated any affected documentation.
• Included tests that validate the fix or feature.
• Checked that related changes are merged.

[coveralls]

coverage: 52.376% (+0.01%) from 52.365%
when pulling 08fdbec on secret-rotation-jobs
into 300d857 on main.

[dmjb]

Changes look good to me, but let's avoid merging until we have rolled out a new encryption key to staging first.