K8SSAND-1828 ⁃ Make keystore-password, keystore, trustore keys in secret configurable

[dnugmanov]

Hi, i want to use client encryption in cassandra, and implement it via cert-manager+k8ssandra-operator. I create certificate via cert-manager and enable following options

spec:
  secretName: ssl-test-jks-keystore
  keystores:
    jks:
      create: true
      passwordSecretRef:
        key: keystore-pass
        name: jks-password

Then cert-manager add in secret ssl-test-jks-keystore with key keystore.jks/truststore.jks, i use this secret in k8ssandraCluster spec, to define my keystore/trustore via clientEncryptionStores section. But k8ssandra-operator and cert-manager hard-coded key name in secret. K8ssandra-operator expect - keystore,trustore, but cert-manager used keystore.jks,trustore.jks .

Could you change default constants according default key of cert-manager or make key name configurable?

https://github.com/cert-manager/cert-manager/blob/2db62c21c337cb5af3ea9dce1cbc0b69cfc7c509/pkg/controller/certificates/issuing/internal/keystore.go#L46

https://github.com/k8ssandra/k8ssandra-operator/blob/32c4fcfdebc5b28b9c731bca8ada9ab79e3910a8/pkg/encryption/encryption_stores.go#L30

Second problem, that keystore-password also hardcoded and expected in the same secret as keystore, cert-manager store it different secret, password secret managed by user, keystore secret managed by cert-managed. According above code keystore will be in secreet ssl-test-jks-keystore secret, password will be in jks-password secret

Could you extend of API encyption.Store to fix following cases and change defaults according cert-manager(or make native support of cert-manager via Certificate resources instead of Secret)?

┆Issue is synchronized with this Jira Task by Unito
┆friendlyId: K8SSAND-1828
┆priority: Medium