Fix and Rewrite setup.py
Fix and Rewrite setup.py

New features:

- Consider the new napp module
- Ignore __pycache__ folder
- Remove deprecated FastLinter
- Add test target with doctest and linter check

Refactoring:

- Use higher-level pathlib for files
- Organize functions into classes
- Solve linter warnings

kytos/kyco-core-napps,cemsbr/kytos-napps,kytos/kytos-napps