Add samples of testing Q# code with classical return values

[tcNickolas]

Part of #1268.
Introduces a shared README.md for all testing samples and includes small edits to existing testing sample.

[github-actions]

Benchmark for 818ada8

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Test	Base	PR	%
Array append evaluation	339.8±2.23µs	338.9±3.78µs	-0.26%
Array literal evaluation	169.6±3.60µs	186.6±1.69µs	+10.02%
Array update evaluation	416.3±1.78µs	416.5±2.48µs	+0.05%
Core + Standard library compilation	24.8±2.26ms	24.3±2.13ms	-2.02%
Deutsch-Jozsa evaluation	4.9±0.06ms	5.0±0.06ms	+2.04%
Large file parity evaluation	34.4±0.22ms	34.6±0.59ms	+0.58%
Large input file compilation	14.2±0.26ms	14.4±0.58ms	+1.41%
Large input file compilation (interpreter)	54.6±2.33ms	55.4±3.07ms	+1.47%
Large nested iteration	33.0±0.38ms	32.6±0.14ms	-1.21%
Perform Runtime Capabilities Analysis (RCA) on Deutsch-Jozsa sample	1581.9±57.50µs	1577.4±58.82µs	-0.28%
Perform Runtime Capabilities Analysis (RCA) on large file sample	8.1±0.17ms	8.1±0.40ms	0.00%
Perform Runtime Capabilities Analysis (RCA) on teleport sample	1447.4±80.09µs	1437.7±62.49µs	-0.67%
Perform Runtime Capabilities Analysis (RCA) on the core and std libraries	28.4±0.62ms	28.1±0.55ms	-1.06%
Teleport evaluation	93.5±3.85µs	93.6±3.64µs	+0.11%

[swernli]

Looking over this made me realize that our test infra doesn't validate stand-alone Python files in our samples. That is out of scope for this PR, so I'll file a follow up. I can see the Rust-based unit test infra automatically picked up the new project as expected, so that means this is consistent with our existing testing strategy.

[github-actions]

Benchmark for 350903d

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Test	Base	PR	%
Array append evaluation	342.6±11.40µs	336.4±2.79µs	-1.81%
Array literal evaluation	168.6±1.59µs	187.3±7.92µs	+11.09%
Array update evaluation	455.9±58.47µs	414.3±2.04µs	-9.12%
Core + Standard library compilation	25.4±0.55ms	24.9±0.59ms	-1.97%
Deutsch-Jozsa evaluation	5.0±0.05ms	5.0±0.11ms	0.00%
Large file parity evaluation	34.4±0.10ms	34.3±0.72ms	-0.29%
Large input file compilation	14.9±0.49ms	14.9±0.40ms	0.00%
Large input file compilation (interpreter)	57.9±2.54ms	56.5±1.37ms	-2.42%
Large nested iteration	32.9±1.10ms	32.7±0.13ms	-0.61%
Perform Runtime Capabilities Analysis (RCA) on Deutsch-Jozsa sample	1575.5±70.14µs	1585.8±127.35µs	+0.65%
Perform Runtime Capabilities Analysis (RCA) on large file sample	8.0±0.09ms	8.0±0.20ms	0.00%
Perform Runtime Capabilities Analysis (RCA) on teleport sample	1459.8±131.19µs	1455.3±100.38µs	-0.31%
Perform Runtime Capabilities Analysis (RCA) on the core and std libraries	28.4±0.26ms	28.4±0.21ms	0.00%
Teleport evaluation	94.5±3.52µs	94.7±5.11µs	+0.21%