[upnpc_] Move to network/ and document graphs

Signed-off-by: Olivier Mehani <shtrom@ssji.net>

plugins/upnpc/upnpc_ → plugins/network/upnpc_

@@ -7,6 +7,13 @@
 
 upnpc_ - Plugin to monitor routers via UPnP
 
+This plugin uses the upnpc utility (package miniupnpc in Debian), to monitor an
+router using UPnP. It can monitor the following aspects, and plot them as separate graphs:
+* uptime: how long the link has been up;
+* bitrate: the up and downlink bitrate (e.g., sync speed for DSL);
+* traffic: the actual up and downstream traffic rate;
+* pkts: the number of packets coming in and out.
+
 =head1 APPLICABLE SYSTEMS
 
 Linux systems with upnpc installed.
@@ -17,7 +24,7 @@ None needed.
 
 =head1 AUTHOR
 
-Olivier Mehani
+Olivier Mehani <shtrom+munin@ssji.net>
 
 =head1 LICENSE