net-mgmt/netdata: broken with libressl{,-devel}

netdata is trying to move forward with crypto versions, and use TLS v1.3
functions. libressl is outdated and does not offer these, so the proper
recourse is marking netdata BROKEN with libressl, rather than weakening its
crypto features by enabling a library.

FreeBSD 12.1 has two suitable openssl implementations currently, one in the
base system (which is also the default), one in ports.

PR: 246027
Submitted by: lysfjord.daniel@smokepit.net