Provide mutilple intermediate representations with their processes in Rust and uses them in python

[Stevengre]

Bring computation heavy taskes like processing kore and kast in Rust from pyk, and reopen them into python using PyO3.

[Stevengre]

• Compare the efficiency between python parser and rust parser. My plan might be: (can be an independent repo)
  • Use benchmark from SV-COMP as the initial target; might be extended with more Rust / Solidity / EVM examples. (OR EVM first? which is one of our best application.)
  • Provide a framework to test and record different functionality under different languages.
• If rust code does have better performance than python, even through python FFI to call rust is faster. Then, we should use Rust to provide efficient and safe representation transformations, multi-process management, modular interpreter and other comutation heavy tasks.

Therefore,

• PyK -> Our programable interface for formal semantics
• RustK -> computation heavy tasks behind the python interface