Simplify Memory::get return type to Option

[fmoletta]

Change Memory::get & Memory::get_maybe to return an Option instead of Result<Option
Change MaybeReloctable::get_int_ref & MaybeReloctable::get_relocatable to return Option instead of Result (previous error had incorrect info)
Fix errors used by the range_check builtin (add info & change name) + remove use of these errors outside of range_check methods
Add error UnknownMemoryCell
Refactor a hint to use get_integer_range instead of using get_range and the checking for None or non-integer valuesl

[codecov]

Codecov Report

Merging #852 (219791c) into main (abaf215) will decrease coverage by 0.01%.
The diff coverage is 97.32%.

@@            Coverage Diff             @@
##             main     #852      +/-   ##
==========================================
- Coverage   96.82%   96.82%   -0.01%     
==========================================
  Files          69       69              
  Lines       28835    28804      -31     
==========================================
- Hits        27920    27889      -31     
  Misses        915      915              

Impacted Files	Coverage Δ
...int_processor/builtin_hint_processor_definition.rs	98.67% <ø> (ø)
...rocessor/builtin_hint_processor/dict_hint_utils.rs	99.22% <ø> (ø)
src/hint_processor/builtin_hint_processor/set.rs	99.18% <ø> (-0.01%)	⬇️
src/utils.rs	99.48% <ø> (ø)
src/hint_processor/hint_processor_utils.rs	88.46% <75.00%> (-0.05%)	⬇️
src/vm/vm_core.rs	97.37% <92.30%> (-0.03%)	⬇️
src/vm/vm_memory/memory.rs	98.99% <95.00%> (-0.02%)	⬇️
src/vm/runners/cairo_runner.rs	97.53% <98.43%> (-0.01%)	⬇️
..._processor/builtin_hint_processor/blake2s_utils.rs	99.49% <100.00%> (+<0.01%)	⬆️
...t_processor/builtin_hint_processor/keccak_utils.rs	100.00% <100.00%> (ø)
... and 15 more

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[juanbono]

LGTM