Add some configuration files for code style tooling
Summary:
Tools:
Code style:
- ClangFormat taken from Sink's configuration with small modifications:
- max width set to 100 characters
- do not pack arguments and initializer list elements
- no space inside brace lists
- EditorConfig: UNIX style text files, 4 spaces for indentation
Reviewers: cmollekopf
Reviewed By: cmollekopf
Tags: Kube
Differential Revision: https://phabricator.kde.org/D10740