M1fixes

[enryH]

I switched to direct imports, but this could be reverted...

Do not import polars:

An issue for M1 Macs is polars, which needs to use the arm instructions. Apparently M1 Macs can use two versions of instructions, but I did not explore the details. Anyways

In mrmr-selection the line

import polars

leads to zsh: illegal hardware instruction.

Therefore I suggest to only import polars if the functionality is requested.

install from GitHub

Allow installation using:

pip install git+https://github.com/smazzanti/mrmr.git

by moving version to metadata (setup.py) and importing the version in the package dynamically.