contrib/bsddialog: import 1.1
Add: slider dialog.
Imported to enable testing and to complete the geomman(8) utility.
Developed as part of the "Full Disk Administration Tool for FreeBSD"
project, Braulio Rivas (brauliorivas@), Google Summer of Code 2025.
Sponsored by: Google LLC (GSoC 2025)
Merge commit '5a70558d32b9680c10ab579c7491652e0838cee4'