[Telemetry] Use psutil for Windows process snapshots.

GetSystemProcessInfo currently invokes WMIC or PowerShell to collect a
process snapshot on Windows. Repeated calls add significant process
startup overhead.

Use the existing psutil dependency to collect the same process
information in-process, preserving the returned data format. Add unit
coverage for the conversion.

Change-Id: I7b85cbf36cf21ba372984042ee292ba182fff206
Reviewed-on: https://chromium-review.googlesource.com/c/catapult/+/8337427
Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Brian Sheedy <bsheedy@chromium.org>