sysutils/sndy: new port

sndy is an audio switching program that allows you to redirect sound
output to any port of your computer. The buttons in the program toggle
the sound output to a different device. The scroll bar can be used to
change the volume level.

PR: 268570
Reviewed by: diizzy, grahamperrin
Approved by: eduardo (mentor)
Differential Revision: https://reviews.freebsd.org/D38518