Support templating of output secrets

[wnagele]

It would be great to be able to template the secrets created by the operator in a similar fashion as sealed secrets is supporting. For instance right now you cannot furnish a dockerconfigjson as you cannot set the type of the resulting secret. Neither can you add more labels/annotations to be able to hook it into other processes.

[brianramseyau]

I came here to add this request, so I will instead add my 2c to this issue instead.

While the above is better than nothing, I feel something more akin to the way that vault-secrets-operator handles it (see the spec for transform here: https://developer.hashicorp.com/vault/docs/platform/k8s/vso/api-reference#transformation) would be "more" useful and robust.

The ability to do significant transforms, add arbitrary secret key/values, etc are fundamentally basic requirements of this kind of system and if we are to take Secrets Manager seriously in the Corporate space (currently heavily dominated by HashiCorp Vault).

While I am trying this out in my HomeLab at the moment, I hope this may evolve in time to be such as a suitable replacement for current tooling.

I do feel however that one of the letdowns is in the SecretsManager itself, in that it can only store single key/value pairs not multiple like other solutions, the saving grace for this 1:1 limitation upstream would be a very robust operator making the trade-off more agreeable.