Add more type and mutability checks

[edg-l]

Checks if a variable is declared mutable and if not, if its being mutated.

Checks for valid mutable borrows (but doesnt check for multiple mutable borrows yet).

[github-actions]

Benchmarking factorial

Compiling factorial (factorial.con)
Finished release in 29.635568ms
Running 5000000 iterations
Using input value: 20
Concrete Result = 2432902008176640000 Time taken : 59.21 ms
Rust Result = 2432902008176640000 Time taken : 60.12 ms

Benchmarking fib

Compiling fib (fib.con)
Finished release in 25.358815ms
Running 5000 iterations
Using input value: 20
Concrete Result = 6765 Time taken : 136.23 ms
Rust Result = 6765 Time taken : 85.19 ms

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 58.92857% with 46 lines in your changes are missing coverage. Please review.

Project coverage is 58.44%. Comparing base (bd93e07) to head (bfc07ea).

Files	Patch %	Lines
crates/concrete_check/src/lib.rs	0.00%	40 Missing ⚠️
crates/concrete_ir/src/lib.rs	87.50%	4 Missing ⚠️
crates/concrete_ir/src/lowering.rs	95.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #124      +/-   ##
==========================================
- Coverage   58.64%   58.44%   -0.20%     
==========================================
  Files          25       25              
  Lines        4258     4361     +103     
==========================================
+ Hits         2497     2549      +52     
- Misses       1761     1812      +51     

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