feat: performance benchmarks

[baszalmstra]

This PR adds a few benchmarks to compare Mun to: Rust, LuaJIT and WASM.

The PR also contains two performance optimizations.

[codecov]

Codecov Report

Merging #104 into master will increase coverage by 0.17%.
The diff coverage is 46.15%.

@@            Coverage Diff            @@
##           master    #104      +/-   ##
=========================================
+ Coverage   78.02%   78.2%   +0.17%     
=========================================
  Files         141     141              
  Lines        9034    8946      -88     
=========================================
- Hits         7049    6996      -53     
+ Misses       1985    1950      -35

Impacted Files	Coverage Δ
crates/mun_runtime/src/lib.rs	86.2% <ø> (ø)	⬆️
crates/mun_runtime/src/macros.rs	64.28% <100%> (ø)	⬆️
crates/mun_runtime/src/reflection.rs	53.7% <44%> (-5.46%)	⬇️
crates/mun_runtime/src/type_info.rs	75% <0%> (+2.5%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 823cdc8...22b9352. Read the comment docs.