Support loading a secret with a HashiCorp Vault token to decrypt sops secrets.

[souleb]

We want to be able to pass a secret containing a HashiCorp Vault token to a kustomization. The Kustomization-controller would pass the token to the Sops Decryptor for decrypting secrets.

This should work like it does with age and pgp, e.g.

apiVersion: kustomize.toolkit.fluxcd.io/v1beta2
kind: Kustomization
metadata:
  name: my-secrets
  namespace: default
spec:
  interval: 5m
  path: "./"
  sourceRef:
    kind: GitRepository
    name: my-secrets
  decryption:
    provider: sops
    secretRef:
      name: sops-vault-token

[kingdonb]

I see that fluxcd/website#681 is a docs change only. Does this adequately explain how to work with Vault now, or is there more work still to do in this issue?

[souleb]

The current doc explain how to do it with the current implementation. This issue is an enhancement that is still to be written.