Simplify Docker SSL handling

[williamjallen]

CDash currently requires SSL/TLS by default when using our production image. While useful for Docker Compose-based systems, this is a major pain point for k8s systems which handle TLS termination at ingress. See #2179, for example. This PR aims to ease these pains by conditionally enabling SSL/TLS if certificates are provided, in preparation for upcoming work to better support k8s-based deployments.

Fixes #2179.

[williamjallen]

@zackgalbreath While the goal was to assist my Helm chart work, this is still very much a draft and I suspect that this may overlap with your work with the UBI image deployment. Feel free to push changes to this PR if you have any suggestions.

[williamjallen]

The tests require the exposed port in the dev environment to match inside & outside the container, in addition to the issues observed by @zackgalbreath with the UBI image. As a result, I switched the port back to 8080.

@zackgalbreath does this resolve the health check issue, or are the certificates the issue?

[zackgalbreath]

@zackgalbreath does this resolve the health check issue, or are the certificates the issue?

The containers spin up successfully but the healthcheck issue remains. Reproducing this manually, the relevant error message is:

Bad Request

Your browser sent a request that this server could not understand.
Reason: You're speaking plain HTTP to an SSL-enabled server port.
Instead use the HTTPS scheme to access this URL, please.

[williamjallen]

An alternative approach might be to simply ping both http://cdash:8080 and https://cdash:8080, and return true if either of them returned a 200.