Add custom TLS cert bundle proxy support of cluster proxy settings

As far as trusted CA bundles, see https://github.com/openshift/enhancements/blob/0d53973f356b4a31bef86bf015a24d06f27bae90/enhancements/proxy/global-cluster-egress-proxy.md for details around how that works (search for 'CAs'). It looks like we create a ConfigMap with a special label and the trusted CA gets injected into that ConfigMap that we can mount and use from our controller.

https://github.com/openshift/cluster-monitoring-operator/pull/602/files is an example of another component creating this ConfigMap and then reading the values from it. That's a good reference for how to create the ConfigMap yaml, but how we read and consume the value from it will likely differ than that example. https://github.com/openshift/console-operator/pull/265/files is another example of how to mount and use this CA bundle from the ConfigMap, although again is not exactly what we'd have to do.