grafana-agent: pyroscope.java component should infer service name for k8s targets similar to ebpf

[korniltsev]

In ebpf we do "ebfp/namespace/container" We should have something similar for java , so that targets do not get merged to "unspecified" in k8s ever

[simonswine]

I think pyroscope.ebpf and pyroscope.java should attach all they knew about the profile collected as internal labels (starting with __). Then we should have a pyroscope.relabel comopnent, that allows us to populate the service_name according to a ruleset.