Remove hard-coded cert-manager configuration and improve TLS docs

[emmanuelmathot]

Fixes #226

This PR removes the hard-coded cert-manager configuration from the Helm chart and updates the documentation with a comprehensive guide for setting up TLS with cert-manager.

Changes:

1. Remove cert-manager annotations from ingress.yaml
2. Simplify TLS configuration in values.yaml to only include essential fields
3. Update unified-ingress.md documentation with:
   • Remove outdated cert-manager configuration
   • Add complete guide for setting up cert-manager with Let's Encrypt
   • Include examples for both staging and production environments
   • Show how to use ClusterIssuer for certificate management

Users can now fully control certificate management through their own annotations, with clear documentation on how to set it up using existing cluster resources.

[batpad]

This is perfct! And I've already tested that this works by adding a custom annotation and setting certManager to false so LGTM.

[sunu]

LGTM!