fix(argo-cd): Fix secret name for applicationset webhook ingress

[pdrastil]

Checklist:

• I have bumped the chart version according to versioning
• I have updated the documentation according to documentation
• I have updated the chart changelog with all the changes that come with this pull request according to changelog.
• Any new values are backwards compatible and/or have sensible default.
• I have signed off all my commits as required by DCO.
• My build is green (troubleshooting builds).

[volker-raschek]

Hi @pdrastil, @mbevc1 and @yu-croco,
this pull request means that a custom secret can no longer be used.

In version 7.5.2 of the helm chart, I am happy that the cert-manager is now primarily used to create certificates, but you have not taken one thing into account.

There are users like me who generate wildcard certificates from let's encrypt. The certificate, stored in a secret, is synchronized via reflector in all necessary namespaces. There it can then be referenced as a secret in the ingress resource.

Because you have now defined this hard coded, the workflow or setup is no longer possible at all and that's very bad.

secretName: argocd-applicationset-controller-tls

Questions and answers that may arise.

1. Why must a wildcard certificate be used?
   Because otherwise the Let's Encrypt API will reveal public DNS names: https://crt.sh/

2. Why can't you create a second wildcard certificate with the same CommonName / SAN?
   Because the client (API's, browsers and so on) would always make a new TLS handshake with HSTS. These TLS handshakes are quite expensive. In my opinion to expensive!

Please provide a fix, so that it's possible to use a custom secret of all ingress resources.