Added API action=zeroconfig (META only) to get all Zero IPs

API module returns a custom mapping of Zero Config IDs to
their corresponding IP ranges (CIDRs) as specified by all
Zero: pages. The result is specifically designed for the 
netmapper varnish module that runs on all varnish servers.

A cron job will download updated configuration and update
local file with this mapping.

Change-Id: Ieb573c8ae9bfde726983603a71db72838355f358
Merge "Added API action=zeroconfig (META only) to get all Zero IPs"