DXF import needs a dedicated import dialog

[furgo16]

Is there an existing issue for this?

• I have searched the existing issues

Problem description

Currently, when either opening (File > Open) or importing (File > Import) a DXF file, and if the "Show this dialog when importing and exporting" setting under Edit > Preferences > Import-Export > DXF has been checked, that same preferences dialog is shown:

While effective for code reusability, the user experience is confusing::

1. why should the preferences dialog pop up if I only want to import?
2. if I change the import settings for the file I'm importing, will it change those settings globally?
3. I'm shown more options than I need (I can choose any setting from unrelated sections)
4. this can lead to inadvertend imports (DXF importer imports file despite clicking on the Cancel button #13620)

This issue proposes to create a dedicated DXF import dialog that is separate from the DXF Import-Export settings page, following #13620 (comment):

1. It exposes the same import section options. That is, the "Show this dialog when importing and exporting", "Use legacy python importer", "Use legacy python exporter", "Allow FreeCAD to automatically download and update the DXF libraries" settings should be in the preferences page only.
2. It should only pop up when invoking File > Open or File > Import and the chosen file in the file picker is a DXF document
3. It should have an OK and Cancel button. OK: go ahead with import, Cancel: cancel operation and do not import anything.

Very crude import dialog mockup

Full version info

OS: Ubuntu Core 22 (ubuntu:GNOME/ubuntu)
Word size of FreeCAD: 64-bit
Version: 0.22.0dev.36999 (Git) Snap 1002
Build type: Release
Branch: main
Hash: ed77603af999525b65dcfc4a41337f15a052c9ef
Python 3.10.12, Qt 5.15.10, Coin 4.0.0, Vtk 7.1.1, OCC 7.7.1
Installed mods: 
  * OpenTheme 2024.4.20
  * BIM 2021.12.0
  * Curves 0.6.35
  * ezydxf
  * ExplodedAssembly
  * BillOfMaterials 0.0.8.2
  * Ondsel-Lens 2024.4.16.01
  * Assembly4 0.50.12

Subproject(s) affected?

File formats

Anything else?

• This issue is concerned with the importer only. A separate issue can be filed for a dedicated export dialog. Arguably, there could be a combined import/export dialog as well. For simplicity of use, this issue advocates for separate import and export dialogs.
• For consistency, other importer's preference should follow the same concept of dual import/settings dialogs. However, the only other importers that have the "Show this dialog when importing and exporting" setting are IFC import and IFC export. If I understand it correctly, they will go away in the near future, so it might not make sense to apply changes to them.
• It might be worth bearing in mind the conversation about rearranging import options at Draft: Add "legacy importer only" to DXF option #13638

Code of Conduct

• I agree to follow this project's Code of Conduct

[maxwxyz]

related: #13599