Add fstyp(8).  This utility, named after its SVR4 counterpart, detects
filesystems.  It differs from file(1) in that it gives machine-parseable
output, it outputs filesystem labels, doesn't get confused by other
formats metadata, and runs in Capsicum sandbox.

Differential Revision:	https://reviews.freebsd.org/D1255
Relnotes:	yes
Sponsored by:	The FreeBSD Foundation


git-svn-id: svn+ssh://svn.freebsd.org/base/head@275680 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f