Request: support importing binary dxf files
#### Summary:
<!-- Summarize the issue/suggestion concisely: -->
If you try to import a binary DXF nothing happend
#### Steps to reproduce:
<!-- Describe what you did (step-by-step) so we can reproduce: -->
- open Inkscape
- open one of the sample file linked below
#### What happened?
- the open dialog close, a new Inkscape Window with the name of the file appear but no data get imported.
- In 1.2-dev, an error message now appears (good)
#### What should have happened?
- DXF should get imported without errors.
Sample attachments:
(Samples from inbox#2076 )
- [2018_-_3d_-_binär_+_Proxy_elemente.dxf](/uploads/00256e961718a061d4467e5938915689/2018_-_3d_-_binär_+_Proxy_elemente.dxf)
- [2018_-_3d_-_Binär_Zeichnung.dxf](/uploads/76690c246fe39ef559c1134aa6bf1a90/2018_-_3d_-_Binär_Zeichnung.dxf)
- [R13_-_3d_-_binär_+_Proxy_elemente.dxf](/uploads/02dbf604cf7416c1f0324acb23f04613/R13_-_3d_-_binär_+_Proxy_elemente.dxf)
- [R13_-_3d_-_Binär_zeichnung.dxf](/uploads/5005a2463a16de1f2da82b946f98f504/R13_-_3d_-_Binär_zeichnung.dxf)
#### Version info
```
Inkscape 1.2-dev (2bad7a816c, 2021-06-14)
```
issue