[FEATURE] Faster than dict?

[Marco-Sulla]

I experimented a little with CPython code. It seems that potentially a C implementation of frozendict can be faster than dict in creation and iteration.
https://github.com/Marco-Sulla/cpython/tree/frozendict/
Benchmark:
https://github.com/Marco-Sulla/cpython/blob/frozendict/frozendict/test/bench.txt

The result is very promising, and maybe I can do a C extension for Python 3.10.

[Marco-Sulla]

Done.