feat(config): add config properties for callback URL components

[ebaron]

This work is done to support the agent auto-configuration work in the operator. Specifically, this is needed to support generating wildcard certificates for the agent to use.

To test:

1. Deploy Cryostat using the operator.
2. Deploy the sample app w/ agent.
3. Swap out the default container image with one built using this PR.
4. Create a headless service:

   apiVersion: v1
   kind: Service
   metadata:
     name: headless
     namespace: cryostat-operator-system
   spec:
     clusterIP: None
     selector:
       app: quarkus-cryostat-agent
     type: ClusterIP

5. Add a POD_NAME environment variable

   - name: POD_NAME
     valueFrom:
       fieldRef:
         apiVersion: v1
         fieldPath: metadata.name
   

6. Add these system properties to JAVA_OPTS_APPEND:

   -Dcryostat.agent.callback.scheme=http
   -Dcryostat.agent.callback.host-name=$(POD_NAME),$(POD_IP)[replace("."\,"-")]
   -Dcryostat.agent.callback.domain-name=headless.cryostat-operator-system.svc
   -Dcryostat.agent.callback.port=9977
   -Dio.cryostat.agent.shaded.org.slf4j.simpleLogger.defaultLogLevel=debug
   

7. Observe a lines similar to:

   2024-11-04 18:41:56:456 +0000 [cryostat-agent-main] DEBUG io.cryostat.agent.ConfigModule - Attempting to resolve quarkus-cryostat-agent-5cd54bbb86-62zsv.headless.cryostat-operator-system.svc
   2024-11-04 18:41:56:546 +0000 [cryostat-agent-main] DEBUG io.cryostat.agent.ConfigModule - Attempting to resolve 10-128-0-67.headless.cryostat-operator-system.svc
   2024-11-04 18:41:56:550 +0000 [cryostat-agent-main] DEBUG io.cryostat.agent.ConfigModule - Resolved 10-128-0-67.headless.cryostat-operator-system.svc to 10.128.0.67
   2024-11-04 18:41:56:552 +0000 [cryostat-agent-main] DEBUG io.cryostat.agent.ConfigModule - Using http://10-128-0-67.headless.cryostat-operator-system.svc:9977 for callback URL
   

Fixes: #525

[andrewazores]

Everything else looks good, just the little note about the README above.