Update readme and example config

cmd/unifi-poller/README.md

@@ -32,7 +32,8 @@ unifi-poller(1) -- Utility to poll Unifi Metrics and drop them into InfluxDB
 
     `sites`          default: ["default"]
         This list of strings should represent the names of sites on the unifi
-        controller that should be polled for data.
+        controller that will be polled for data. Pass `all` in the list to
+        poll all sites.
 
     `interval`       default: 30s
         How often to poll the controller for updated client and device data.

up.conf.example

@@ -5,6 +5,7 @@
 
 # If the controller has more than one site, specify which sites to poll here.
 # If only one site, "default" is likely the correct name.
+# Set this to ["all"] to poll all sites, no matter their names.
 #sites = ["default"]
 
 # The Unifi Controller only updates traffic stats about every 30 seconds.