Apply consistent Styleguide

Currently there is a reasonably well defined .editorconfig in place. It's not consistently followed.
A `dotnet format` is in order with some manual cleaning up here and there.

Start by reading the repository's .editorconfig and checking how dotnet format is configured or invoked. Run dotnet format, then inspect the remaining manual formatting differences across the project. The work is done when the code consistently follows the existing styleguide and no manual cleanup remains.

Written by the indexing model from the issue text.