Generation handling of SSO secret

[mjnagel]

          @mjnagel - per our convo, perhaps we ought to do [something similar to what is done with netpols](https://github.com/defenseunicorns/uds-core/blob/main/src/pepr/operator/controllers/network/policies.ts#L95)  with generation

Originally posted by @MxNxPx in #511 (comment)

[mjnagel]

Updating with more context...

Currently we generate a secret as part of the sso flow in the operator. My current understanding is that if someone changed the secretName we would not be cleaning up the previous secret. To handle this we can probably add the generation label and filter to delete orphaned secrets similar to what we do for network policies.

For other cases:

• the client is updated but secret name stays the same, secret is updated, no need to cleanup
• client is deleted, ownership linking will cleanup the secret for us

[mjnagel]

Specific behavior we can mimic here (links for network policies):

• Add generation label to secret: https://github.com/defenseunicorns/uds-core/blob/main/src/pepr/operator/controllers/network/policies.ts#L95
• Filter/delete any older generation secrets: https://github.com/defenseunicorns/uds-core/blob/main/src/pepr/operator/controllers/network/policies.ts#L114-L129

[mjnagel]

Confirmed this is a bug, working to add the generation / purge logic.