dev: expose serialize in RustVM pythonic hints

[enitrat]

Exposes a serialize function, available in the scope of all hints, that enables the serialization using serde of cairo types, and returns their python representation.

This can be used for the logging / tracing system.

I am welcoming any alternative idea on the currently proposed design - as working with python globals() has been quite a hassle.

Also, i'm not sure yet how we can make this entirely transparent with the pythonVM runs. If we realize there's a need for that, we can do it later.

This does introduce a small performance overhead of about ~5% from what i've observed empirically. So in production we'll need to make sure we're not compiling with this flag.
Closes #883

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.24%. Comparing base (e81b61c) to head (cc2cb5c).
Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #887      +/-   ##
==========================================
- Coverage   81.92%   78.24%   -3.69%     
==========================================
  Files          64       64              
  Lines       15320    16746    +1426     
==========================================
+ Hits        12551    13103     +552     
- Misses       2769     3643     +874     

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