Contribution process improvement

[IvanFilipov]

@Angeld55 consider adding code of conduct.

It will be helpful for all of the contributors to know which styles are acceptable for this repo.

You might as well take a look at https://github.com/IvanFilipov/FMI-DSA/blob/master/CODING_STYLE.md

[IvanFilipov]

Also .editorconfig could useful - https://github.com/IvanFilipov/FMI-DSA/blob/master/.editorconfig.
It is respected by most of the IDEs