Add an .editorconfig file, so we can have some consistency in the project. (I
don't care what settings we use, as long as we all use the same.)
Use four spaces as default (Python default, as suggested by Henrik).
- Legacy-Id: 10595
Note: SVN reference [10551] has been migrated to Git commit 769d443581
Note: SVN reference [10553] has been migrated to Git commit 82ad203627
