MFH: r502951 x11/cinnamon: Remove unnecessary version check

Bug 237426 updates Pillow to 6.0.0, which removed the Image.VERSION
variable, after a period of deprecation.

Cinnamon currently uses this variable, so backport upstream commit
c843f3664064742e2672e0fea528571a882d84ad [1] to compensate, so we don't
need to wait for the Gnome teams Cinnamon 4 update, which has already
pulled it in. Thanks to Charli Li for pointing this commit out.

While I'm here, fix all stage-qa errors and ports/framework compliance
issues:

• Add missing LIB_DEPENDS
• Add missing USE_{GNOME,X11} components
• Add USES=gnome, gl
• Fix gstreamer dependencies (GSTREAMER1, not GSTREAMER)
• Add LICENCE{_FILE}
• Fix more/all shebangs, remove custom REINPLACE_CMD section
• Remove GH_ACCOUNT (no longer necessary)

[1] https://github.com/linuxmint/cinnamon/pull/8496
[2] https://github.com/linuxmint/cinnamon/issues/8495

PR: 238070, 237426
Reported by: kai
Tested by: Michal Kilijanek (via Twitter)
Approved by: kwm (gnome, maintainer)

Approved by: ports-secteam (blanket(s): bugfixes, dependencies)