Added SNI support for JWT secrets retrieved from HTTPS URL

[fabriziofiorucci]

Proposed changes

The current NGINX Ingress Controller implementation doesn't set the SNI field when fetching the JWT secret from an HTTPS URL. This breaks compatibility with idPs requiring SNI to be set.

This PR adds two directives to turn on SNI and set the hostname.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

[fabriziofiorucci]

Changes reviewed