MFC: r265263
MFC: r265263

Make this manpage ready for hardware notes generation, add more Xrefs and perform
general cleanup.

In particular, don't claim rsu(4) devices can be configured with hostname(1)...

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase