[Doc] Documentation missing for backstage TLS configurations

[Zaperex]

What do you want to improve?

We need documentation for configuring TLS for backstage. Many institutions and organizations have their own CA certification for traffic in their internal networks, and we need to document on how to configure backstage to recognize those as secure certifications (not self-signed).

What is the current documentation?

There is no documentation at the current time.

What is the new documentation?

Documentation on how to configure TLS for backstage.

[coreydaley]

@Zaperex Since this will be running on Kubernetes clusters and not bare metal, would you be OK with just pointing to documentation for OpenShift, EKS, etc that details how to implement TLS on those specific providers?