[Epic] Kubernetes/OpenShift awareness

[andrewazores]

There are various things we can try to do to improve the Agent's ergonomics when it detects it is running in Kubernetes/OpenShift.

• [Task] detect default service account token and try to present this for Cryostat authorization, if nothing else specified #382
• watch mode as specified in feat(attach): implement basic dynamic attach #234 (comment)
• ability to mount Agent JAR as a volume into workload Pod, or copy in (a la oc cp or oc rsync), then do the equivalent to oc exec to launch the Agent JAR
• can the Agent inspect itself/its Pod to look for annotations? These could also be used to set configuration property values, ex. the Cryostat server URI, so that the configuration can be done by annotation rather than environment variable
• ability to detach and stop the Agent process separately from the workload process. This would facilitate an ability to restart the Agent, which would be useful when combined with loading configuration properties from annotations or other sources that do not force the Pod to rolling restart