Explore and support per-process or per-job power reporting (multi-tenancy)

[tpatki]

Learn from scaphandre and see if we can add similar features to Variorum (or to LDMS and Flux).

https://hubblo-org.github.io/scaphandre-documentation/explanations/how-scaph-computes-per-process-power-consumption.html

https://hubblo-org.github.io/scaphandre-documentation/index.html