games/lugaru: Update to 1.2

• Switch to gitlab repo, where the game is actually maintained.
• Bump PORTEPOCH as the versioning scheme changed.
• Update license information.
• Switch to sdl2.
• Remove obsolete DESKTOP_ENTRIES and link from share/pixmaps: the software now provides a lugaru.desktop file and an icon in share/icons.

Reviewed by: tcberner (co-mentor)
Approved by: gerald (mentor)
Differential Revision: https://reviews.freebsd.org/D24992