feat(reports): add auth proxy protecting report generators

[andrewazores]

Fixes #204
Fixes #207

1. Adds an auth proxy container to each report replica Pod. This is oauth2-proxy normally, or else openshift-oauth-proxy if OpenShift authentication is enabled
2. Regardless of which proxy container is deployed, it is configured to only use Basic auth
3. A Secret containing a randomly generated access key and a corresponding htpasswd file is created. The htpasswd file is loaded by the auth proxy to set up its Basic auth. The access key is referenced by Cryostat so that it can be used for Basic authentication on Cryostat's internal REST client which it uses to send requests to the report generator service.
4. If the proxy is an openshift-oauth-proxy, then the automatic OpenShift TLS configuration is picked up and the Service points at the proxy's HTTPS port. Cryostat is configured to trust all certificates and not verify hostnames in this case (see [Epic] TLS configuration enhancements #168). If the proxy is oauth2-proxy then the communications are done over unencrypted HTTP.

The end result should be that, if a report generator deployment is created (--set reports.replicas=n, where n>0), then requests sent to these Pods or the Service in front of them will require the client to pass an HTTP Basic authentication check. This check uses a hardcoded username, but a generated secret for a password. This helps prevent abuse of the report generator by other cluster workloads asking the report generator to process JFR files when they are not part of the Cryostat deployment.

To test:

1. Install the Helm chart as usual, but with --set reports.replicas=1 to configure a report generator deployment.
2. Visit the Cryostat UI, create a sample application or define the localhost:0 custom target, and request an automated analysis report
3. Verify that the report is generated successfully
4. Inspect the Pod logs and verify that the report generator Pod serviced the request
5. Launch a shell within the cluster (via OpenShift UI, or kubectl exec on ex. the Cryostat container) and do curl -vk http://cryostat-reports.mynamespace.svc:10001/report. Change the scheme to https if deployed with OpenShift authentication enabled. This should result in an HTTP 403.

[ebaron]

Looks good, just a small thing I noticed