feat: add ExternalSecret to sync wave task

[ckav370]

I want to be able to use a preSync hook to run some database migrations. This has been working fine, until such a time as updating the container secrets which are using the External Secret Operator and CRD to create a k8s secret which the job created by the preSync hook creates mounts.

As per this Github issue #9891, the recommended approach is to use Argo sync waves. However ExternalSecret is not included in one of the predefined kinds and therefore cannot be part of a different "wave" meaning that any secrets defined by ExternalSecrets cannot be synced before the preSync hook as part of the pre Sync wave.

This would allow the ExternalSecret to have an annotation such as the following

argocd.argoproj.io/sync-wave: "-2"

And a preSync hook to have a greater weighted sync wave such as

argocd.argoproj.io/sync-wave: "-1"

And all other resources which are part of the deployment would default to weight of 0 without the need for an annotation

[piotrplenik]

Related to #612