[heft] Add `--trace` parameter to Heft to emit timeline trace in Chrome Trace Events format

[dmichon-msft]

Summary

Adds support for heft --trace <command> to record a timeline view in Chrome Trace Events format of all tap invocations.

Details

Logs all tap invocations, listing the name of the plugin and of the hook. The stack view is a bit misleading due to the viewer assuming that durations that fully intersect other durations are sub-operations.

How it was tested

Running locally to compile rush-lib, and loading the output file into Edge Dev Tools.