FreeBSD build instructions in wiki

Hello all,

I have added some simple build instructions for FreeBSD to the wiki :
These are off the top of my head as I do not have access right now to a
clean FreeBSD install to test, If someone could walk though them on a
system and record all dependencies that would help. I will do it my self
the end of the week ether way, Also if you see anything wrong please do

I hope we can get the instructrions down to just typing “cd
/usr/ports/comms/gnuradio && sudo make install clean” but until I hope

Thank you.