Add benchmark script

[CohenArthur]

• parser: WIP: Parse empty types -> Read message
• empty_types: Add empty type parsing and instantiation
• empty_types: Instantiate empty types on the fly
• benchmark: WIP: Add base for bench script
• stdlib: Add NoReturn type
• stdlib: Add Args.count() function
• functions: Allow as_bool() on function calls and method calls

[codecov-commenter]

Codecov Report

Merging #384 (1307561) into master (f629a73) will decrease coverage by 0.76%.
The diff coverage is 64.07%.

@@            Coverage Diff             @@
##           master     #384      +/-   ##
==========================================
- Coverage   91.73%   90.96%   -0.77%     
==========================================
  Files          37       38       +1     
  Lines        3979     4075      +96     
==========================================
+ Hits         3650     3707      +57     
- Misses        329      368      +39     

Impacted Files	Coverage Δ
src/instruction/binary_op.rs	81.55% <0.00%> (-7.81%)	⬇️
src/instruction/function_call.rs	79.47% <0.00%> (-3.96%)	⬇️
src/instruction/method_call.rs	74.54% <0.00%> (-7.46%)	⬇️
src/instruction/mod.rs	67.64% <ø> (ø)
src/instruction/var_or_empty_type.rs	90.00% <90.00%> (ø)
src/builtins.rs	95.91% <100.00%> (+0.17%)	⬆️
src/parser/constructs.rs	99.13% <100.00%> (+0.01%)	⬆️
src/instruction/var.rs	80.48% <0.00%> (-9.76%)	⬇️
src/context/scope_map.rs	94.96% <0.00%> (+0.71%)	⬆️
src/instruction/type_instantiation.rs	91.46% <0.00%> (+3.04%)	⬆️

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[CohenArthur]

What remains is to add an actual script to benchmark: One that could be parser intensive, one that would be typechecker intensive and one that would be execution intensive (+ generic intensive etc etc when those are implemented).

Then, a timing logic, so that we can measure the time it takes to run the interpreter on those benching scripts.
Finally we just need to display the results properly