Retrieving GPU power counters via `CUpti_ActivityEnvironment`

Recently there is some interest around GPU power draw (e.g., https://github.com/pytorch/pytorch/pull/132936), because large scale training consumes power at an unprecedented scale that affects datacenter power delivery and the grid.

Along that line, I was wondering if Kineto is interested in incorporating power draw information via the CUPTI activity API, specifically CUpti_ActivityEnvironment.

I'm no expert in CUPTI or Kineto, but since CUPTI activities are already being used in the codebase, I thought it might not be too hard to add this. If this aligns with the project's direction, I am willing to contribute this feature myself. But to be real honest, I have practically zero experience with CUPTI or using Kineto, so I might need a little handholding and time.

Start by examining Kineto's existing CUPTI activity integration and the CUPTI_ActivityEnvironment API documentation. Determine how power-counter records would be collected and represented, then define validation for exposing GPU power-draw data in profiler output; the issue names no files or tests.