Implement file chooser .inx parameter for extensions
A feature that has been requested often is a file chooser implementation that can be used as an .inx parameter.
As many extensions currently need to support filenames through plain string parameters this seems like a useful enhancement.
Open questions regarding implementation:
- do we need dedicated file/folder pickers or is a general picker that selects files and folders fine?
- do we need multi-selection or is a single selection sufficient?
- do we need file type filtering?
Extension authors who wish to use this feature are encouraged to comment and share their needs, so we can tailor this feature accordingly.
Original issue: https://bugs.launchpad.net/inkscape/+bug/1070193