Update to upstream version 3.0.5821, fix dependencies and improve pkg-msg

• Update multimedia/emby-server to 3.0.5821
• Remove dependency on multimedia/libmediainfo (now uses FFMpeg instead)
• Add X11 OPTION (ON by default) for user to choose dependency of graphics/ImageMagick or graphics/ImageMagick-nox11
• Improve pkg-message to prompt the user to some additional options that can be set when building multimedia/ffmpeg and graphics/ImageMagick in order to optimise their Emby Server experience.

PR: 206374
Submitted by: joshruehlig@gmail.com
Reviewed by: woodsb02@gmail.com (maintainer)
Approved by: woodsb02@gmail.com (maintainer)