Add support for existing backup credentials

[donch]

Currently, the cluster chart create a secret containing backup credentials like S3. There is no way to provide a existingSecret to avoid putting these credentials in the Helm Values.

[DASPRiD]

I was just about to set up my first cluster and ran into that problem as well. Since we are using GitOps, it's anything but ideal to store the secret access key straight in Git.

[mrclrchtr]

Same here. I can not store the secret in the values file.

[SalvoRusso8]

Hi all, any update about this feature? I think is very important to permit the use of an existing secret to allow the use of this chart with tools like fluxcd

[itay-grudev]

@SalvoRusso8 There is PR that implements this: #239. Would you be able to test that and confirm it works?