Add benchmark for generated munlib file sizes

[Wodann]

• [x] claim this issue (assign yourself or comment below)
• [x] setup repository on your local machine and make sure all tests pass (cargo test)
• [x] read our contributing guidelines
• [ ] add a benchmark that compiles the Mun packages in examples/ and records the *.munlib file sizes
• [ ] add a ci job that runs benchmarks on main and reports a warning if files sizes have increased.
• [ ] (BONUS) Figure out a way to plot a graph, either in Rust or on our website to show the history of *.munlib file sizes.
• [ ] start a Pull Request. Set description to closes #419. If this is your first PR, welcome :tada: :smile:

Depends On

• [ ] #419

[alexandrasp]

@Wodann, I will start with this one. Could you assign it to me?

[Wodann]

Great choice, thank you!