V3beta - Python improvements

[M4RC0Sx]

This PR covers the following aspects:

• Use PEP8 format in all files, style improvements.
• Migration to Pipenv in order to improve dependency management and local development environment with dev dependencies and .env management provided by Pipenv.
• Implemented a custom FlareSolverr logger to avoid having to disable all libraries loggers.

[HLFH]

@M4RC0Sx Have you added pyproject.toml in this PR? PEP 517
If not, you should as it will help packaging for GNU/Linux distributions.