[Request] Configuration to grab env vars/system properties and include in registration target node labels/annotations

[andrewazores]

cryostatio/cryostat#635 (comment)

Following on from that discussion, it would be useful for users to be able to configure the Agent to include various things into the node labels and annotations on the Target node that the Agent publishes to the Cryostat server representing itself. These could be specified as MicroProfile Config properties as generic Maps (one for labels and one for annotations). At deployment time, the user can choose to set the values as hardcoded values or to set them by referencing other environment variables. This way, the user can do things like capture Kubernetes Downward API values and embed these into node labels/annotations.