deskutils/lookbook: update to 2.0.0

ChangeLog: https://github.com/elementary/iconbrowser/releases/tag/2.0.0

• Fancy new icon
• Drag the window from anywhere
• Follow the system dark style preference
• Updated for Gtk 4

Move the port to its official name.
Mantainer MIA for some time now with this and other ports.

PR: 266839
Reported by: duchateau.olivier@gmail.com
Approved by: greg@unrelenting.technology (maintainer, timeout)