Batch Export - Export layers - option to respect page boundaries
#### Summary:
I use Inkscape to create designs that I use to cut/engrave stuff with a laser engraver.
For this, I create two layers. One for engraving. One for cutting.
I currently manually generate
- one SVG file for cutting
- one png file for engraving
For this, I use the _Single Image / Page_ export functionality with manually set parameters.
The _Batch Export / Layers_ functionality would be easier/quicker to use. BUT... the layers are exported at a minimum size.
An option to export the layers at the page size would be perfect for my use case.
#### Sample attachments:
#### Version info
```
Inkscape 1.2-alpha1 (b6a15bbbed, 2022-02-23)
GLib version: 2.70.4
GTK version: 3.24.31
glibmm version: 2.66.2
gtkmm version: 3.24.5
libxml2 version: 2.9.12
libxslt version: 1.1.35
Cairo version: 1.17.4
Pango version: 1.50.4
HarfBuzz version: 3.4.0
OS version: Windows 10 21H2
```
issue