Create keycloak prod configuration

[corneliusroemer]

As part of perf issues with keycloak, and as part of #961, I'm trying to setup keycloak for prod in #959

Just switching from --start-dev to --start doesn't seem to be enough. I get:

Changes detected in configuration. Updating the server image.
Updating the configuration and installing your custom providers, if any. Please wait.
INFO  [io.quarkus.deployment.QuarkusAugmentor] (main) Quarkus augmentation completed in 5124ms
Server configuration updated and persisted. Run the following command to review the configuration:

	kc.sh show-config

Next time you run the server, just run:

	kc.sh start --optimized

ERROR: Unexpected error when starting the server in (production) mode
ERROR: Failed to start quarkus
ERROR: Strict hostname resolution configured but no hostname setting provided
For more details run the same command passing the '--verbose' option. Also you can use '--help' to see the details about the usage of the particular command.

[chaoran-chen]

@theosanderson, @corneliusroemer, what are the steps that we need to do here? Would you consider this as a mandatory task for the MVP?

[theosanderson]

I'm content for MVP with current set up