Rename the Python package to daynivo_kiosk

src/voxip_kiosk -> src/daynivo_kiosk, with every import, the launchers,
install.sh, the Makefile and the manager's gunicorn app path. An upgrade
replaces /usr/lib/voxip-kiosk/python as a whole, so the old package
disappears; tested by upgrading an installation of the previous commit.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

bin/voxip-kiosk-agent

@@ -4,6 +4,6 @@ import sys
 
 sys.path.insert(0, "/usr/lib/voxip-kiosk/python")
 
-from voxip_kiosk.agent import main  # noqa: E402
+from daynivo_kiosk.agent import main  # noqa: E402
 
 sys.exit(main())