Integrate RPCN dashboard into observability repo

[hcoyote]

Ash has some stuff stubbed out here. Let's figure out how to integrate into this repo. The current dashboard is json based, so we'll want to turn it into something with jsonnet/grafonnet probably, to align with how we want to take this repo forward for redpanda core.

https://github.com/redpanda-data/connect/tree/main/resources/docker/profiling