Allow constructing SecretOperatorVolumeScope from user-provided string

[sbernauer]

Description

Follow up of #342
Now superset-operator can constuct SecretOperatorVolumeScope from user-provided string from AuthenticationClass CRD

Review Checklist

• Code contains useful comments
• (Integration-)Test cases added (or not applicable)
• Documentation added (or not applicable)
• Changelog updated (or not applicable)
• Cargo.toml only contains references to git tags (not specific commits or branches)

Once the review is done, comment bors r+ (or bors merge) to merge. Further information

[nightkr]

Hm... I'm a bit inclined to think that I'd rather either like to express this in a more YAML/serde-native way immediately, something like:

bindCredential:
  secretClass: foo
  scope:
  - pod: {}
  - service: bar

Or just upstream the scope decoding logic from the secret operator. The comma-separated list is "just" a consequence of the CSI stuff only allowing a string-to-string map for options, not because that's actually a good API when given some more freedom.

[sbernauer]

Ok, so we then modify the AuthenticationClass CRD to something like this?

apiVersion: authentication.stackable.tech/v1alpha1
kind: AuthenticationClass
metadata:
  name: myldap
spec:
  protocol:
    ldap:
      hostname: ldap.server
      port: 389
      domain: domain.local
      bindCredentials:
        secretClass: superset-with-ldap-ldap-bind
        scope:
          node: {}
          pod: {}
          services:
            - myservice

[sbernauer]

Going to close this, as we agreed on adopting the CRD