feat: rename instrumentation to simulation

[GuillaumeLagrange]

instrumentation is still accepted as an input, but it maps to simulation internally, as we plan to phase it out.

[codspeed-hq]

CodSpeed Performance Report

Merging #150 will degrade performances by 29.96%

_{Comparing cod-1441-accept-simulation-as-a-value-instrumentation-which-is-now (9181bce) with main (03f528f)}

Summary

⚡ 4 improvements
❌ 5 regressions
✅ 357 untouched

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Mode	Benchmark	BASE	HEAD	Change
⚡	WallTime	large_drop	808.1 µs	776.8 µs	+4.02%
⚡	WallTime	count_chars_in_string	33 ns	32 ns	+3.12%
❌	WallTime	filter_items_with_counter	802 ns	1,145 ns	-29.96%
❌	WallTime	iterative[5]	7 ns	8 ns	-12.5%
❌	WallTime	recursive_memoized[BTreeMap<u64, u64>, 10]	581 ns	608 ns	-4.44%
⚡	WallTime	sort_unstable	130.6 µs	109.9 µs	+18.84%
❌	WallTime	generate_gray_code[1]	159 ns	164 ns	-3.05%
⚡	WallTime	system_time	13 ns	12 ns	+8.33%
❌	WallTime	sleep_100ns	185 ns	193 ns	-4.15%

[MichaReiser]

Note that this was a breaking change because it changes the location of the benchmark binary (it's now stored under target/codspeed/simulation/<bench> and not target/codspeed/instrumentation/<bench>)

[GuillaumeLagrange]

@MichaReiser Indeed, although we do consider this implementation details, as we recommend caching target/release which makes cargo-codspeed only copy the linked benchmark binary to target/codspeed/<mode> from target/release. This is why we did not make it a major.

Thanks for pointing this out and sorry for the frustration.