Checklist

• I've searched the issue queue to verify this is not a duplicate feature request.
• I've pasted the output of kargo version, if applicable.
• I've pasted logs, if applicable.

Proposed Feature

Allow for easier passing of urls instead of requirement to redeploy whole helm chart. E.g. looking for secrets with specific labels.

Motivation

With sharded architecture, onboarding new shard requires redeployment of the kargo chart on hub to load additional argocd url. This could be simplified with secrets as those can be created and deleted much easier, without adding the need to redeploy whole app.