multimedia/emby-server: Update to 4.6.6.0

Update emby-server and the embedded ffmpeg built. Streamline the
configure target with upstream. Samba support has been dropped.

Changes: https://github.com/MediaBrowser/Emby.Releases/releases/tag/4.6.6.0
Approved by: philip (mentor)
Differential Revision: https://reviews.freebsd.org/D33063