New ports: games/voxelands and games/voxelands-server

A voxel sandbox game forked from minetest:
http://www.voxelands.com/

PR: 201069
Submitted by: dcmenche@gmail.com (maintainer)
Reviewed by: mat
Approved by: swills (mentor)
Differential Revision: https://reviews.freebsd.org/D8379