[heft] Add auditing in rushstack CI/CD to catch performance regressions

[dmichon-msft]

Summary

We should add a benchmark test project that runs various common scenarios for Heft, leveraging V8 code coverage to collect information on:

item	unit	source
Executed Code	KiB	V8 Code Coverage
Unused Code	KiB	V8 Code Coverage
Loaded Code	KiB	V8 Code Coverage
Loaded Files	#	V8 Code Coverage
Duration	ms	time / cpuprofile

Once we have this data being generated, we should have a baseline CI pipeline that calculates a new reference value for every commit into main, and then have the PR CI job do performance comparisons and look for regressions/improvements. This will help us catch performance regressions and give us a standard for evaluating impact of optimizations.

This is the same concept as #5691 , but targeting @rushstack/heft

Candidates for benchmarking

• heft --help
• heft run --only build in demo projects using our published rigs.
• heft run --only test in demo projects using our published rigs.