Implement Editor config.

**Is your feature request related to a problem? Please describe.**
When editing an existing configuration, the elements will get placed at the wrong indentation. This results in a harder to read configuration.

**Describe the solution you'd like**
Implement an [editor config](https://editorconfig.org/).

**Describe alternatives you've considered**
* Some important settings could also be set via the configuration settings. It makes sharing individual configurations better. But having to place these details in each and every configuration could be tedious.
* Another solution is to detect the used tab space.