Migration to pyproject.toml? (PEP 517, 518 support)

[nullableVoidPtr]

I can do this in a PR, but I wanted to ask if there were any objections before I get started on this.

As of recently, setup.py has been considered deprecated in favor of a build-system independent format.
Seeing as qiling only uses setuptools anyways, the plan to migrate the package to PEP 518 is to specify only setuptools in the pyproject.toml file, alongside dependencies, license, and other metadata.
This setup would either shrink or remove setup.py entirely; setuptools itself does not support editable installs without a setup.py, but that has a workaround in pip, although this mandates a minimum pip version of 21.3.

[elicn]

Keeping up to date with the standard is always good, but we have leave some room for slower user adoption (meaning not moving forward too fast). Specifically, this project made a decision to move to Python 3.8 just recently, so we have to make sure this change doesn't break anything.

That being said, I think this is a great idea.

[xwings]

Close for now.

We updated the codebase for Qiling and Unicorn since this issue being posted.

Feel free to try the latest version.