Low hanging fruits

[r0mainK]

1. Added a couple PEP8 exceptions:

• E203:
• E731: sometimes we want lambda expressions
• D105: magic method docstrings not necessarily required
• D202: causes conflicts if you define a function in a function

2. VSCode in gitignore for custom config

3. Setup.py: removed python 3.5/3.4, using pathlib, corrected formatting

4. Swith to Ubuntu 18.04 in Dockerfile

5. Fix linting requirements, add black to it for pretty formatting

6. Add myself MAINTAINERS (I think that may be why I can't add you as a reviewer ?) file and rename it, rename CODE OF CONDUCT and CONTRIBUTING guidelines + remove trailing line and smalll typo. I don't know why this repo is the only one which does not have these files captalized