audio/libvgm: update to latest GitHub commit and improve port

Improvements include:

• switch to build shared libraries so that they are usable for other apps
• optionize bundled commands (ON by default)
• rename "player" command to "libvgm-player" (player is too generic name and can cause filename clashes)

Co-authored-by: Daniel Engberg <diizzy@FreeBSD.org>

PR: 281363
Reported by: diizzy