[FEATURE REQUEST] Vault: Distribute authentication details using response wrapping

[lkubb]

Is your feature request related to a problem? Please describe.
The Salt master fetches Vault authentication details in plaintext and distributes them over its own channels, even though Vault provides an integrated mechanism specifically for this purpose: response wrapping.

Describe the solution you'd like
The Salt master should request wrapped responses and distribute the resulting response wrapping tokens to minions. They can then request the secret from Vault directly, ensuring integrity, secrecy and auditability.

Describe alternatives you've considered
Keep distributing the data as is.

Additional context
https://learn.hashicorp.com/tutorials/vault/pattern-approle?in=vault/recommended-patterns#anti-patterns (Mostly tangential since the Salt master needs to be 100% trusted anyways, but mentions auditability).