games/sdl_jewels: Improve port, take maintainership

• Replace PORTVERSION with DISTVERSION.
• Update MASTER_SITES and WWW.
• Add LICENSE.
• Fix dependency - prevent silent grab libgl.
• Sort USE_SDL.
• Fix warnings from portclippy.
• Format DESKTOP_ENTRIES.

PR: 288143
MFH: 2025Q3
(cherry picked from commit 4f742feef1fa66b1d059fcb9efeb8bef469cd19b)