Proposal for adding "firewall_myservices_udp" in etc/rc.conf

For a simple workstation, we can use this simple configuration in
/etc/rc.conf:
firewall_type="workstation"
firewall_enable="YES"
firewall_myservices="22,80"
firewall_allowservices="any"

But the firewall_myservices allows only TCP services.
It's not possible to declare UDP services (like a torrent client).

This patch propose to add UDP services by 2 changes:
1. firewall_myservices became a deprecated alias, the new is
firewall_myservices_tcp
2. A new firewall_myservices_udp variable is added.

Patch attached to PR194292:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=194292

What do you think ?