Add `Qtest` library that uses class constraints #8880

Job	Run time
Clippy	35s
Format Q# Files	52s
Format	23s
Build and test (windows-latest)	10m 31s
Build and test (ubuntu-latest)	5m 40s
Integration tests (windows-latest)	11m 45s
Check web files	27s
Rust Unit tests (windows-latest)	6m 10s
Integration tests (ubuntu-latest)	5m 52s
Build and test (macos-14)	6m 46s
Rust Unit tests (ubuntu-latest)	3m 2s
Integration tests (macos-14)	6m 0s
Rust Unit tests (macos-14)	3m 24s
Status Check	0s
	1h 1m 27s

Provide feedback