feature: Make it easy to push config through a shared drive/location

[Enissay]

✨ Describe the feature you'd like

I have 5 nodes which are easy to maintain via a shared drive.
Pushing config for each in ./node${i}/config/vault-unseal.yaml on the said shared drive.
Sadly they all remain in the shared drive unless I move them away, which makes the whole process pointless.

It would be nice to:

• load the config from folderA => my case the sahred drive
• save it to folderB (working dir) => some location on the host
• optionally delete it from folderA => or it can be done manually as well, what is important is that it doesn't rely on folderA anymore

Unless you might suggest another way todo.

🌧 Is your feature request related to a problem?

No response

🔎 Describe alternatives you've considered

Manually login into each node and apply the needed changes before launching the cluster.

⚠ If implemented, do you think this feature will be a breaking change to users?

Not sure

⚙ Additional context

It won't affect the others necessarily, it can be made optional.

🤝 Requirements

• I have confirmed that someone else has not submitted a similar feature request.
• If implemented, I believe this feature will help others, in addition to solving my problems.
• I have looked into alternative solutions to the best of my ability.
• (optional) I would be willing to contribute to testing this feature if implemented, or making a PR to implement this functionality.

[Liam Stanley]

I'm not sure there is value in supporting this in vault-unseal itself -- I don't see others being likely to reuse this kind of logic. This seems like something that should be handled via the method you use to actually deploy vault-unseal itself.