feat: Added .editorconfig to project, including Maven plug-in.

[Oliver-Loeffler]

Issue

Fixes #485

Adds a very basic .editorconfig to the project and the related Maven plug-in to automatically format files on demand. README.md has been updated accordingly on how to make use of EditorConfig and where to get the plug-in's for the IDEs.

Progress

• [x] Change must not contain extraneous whitespace
• [x] License header year is updated, if required
• [x] The PR name must follow the pre-defined format
• [x] Verify the contributor has signed Gluon Individual Contributor License Agreement (CLA)