[ENH] Move Vault secrets and provider auth to custom action

[viniciusdc]

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What does this implement/fix?

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• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds a feature)
• [ ] Breaking change (fix or feature that would cause existing features not to work as expected)
• [ ] Documentation Update
• [ ] Code style update (formatting, renaming)
• [ ] Refactoring (no functional changes, no API changes)
• [ ] Build related changes
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[marcelovilla]

@viniciusdc is this ready for review? Is there an associated issue?

[marcelovilla]

@viniciusdc with Vault failing relatively frequently, I'm wondering if we should consider just using GitHub secrets instead. Any thoughts?

C.C. @Adam-D-Lewis @dcmcand

[dcmcand]

I would be in favor of moving away from vault

[marcelovilla]

I opened https://github.com/nebari-dev/nebari/issues/2835

[marcelovilla]

We're going to address https://github.com/nebari-dev/nebari/issues/2835 so we won't be merging this PR