Feature: Add option to export all lines with minimal width in dxf exports

An optional setting has been added to dxf exports that will allow users to write all lines with minimal width 0 (hairline).
Lines within DXF files having zero width typically remain minimal in the CAD regardless of zoom level, so this functionality can be quite useful for compatibility with exported DXFs that are edited with other software, especially in use cases where high data density is a concern.

This feature was funded by Stadtwerke München

This feature was developed by mhugent