Switch hard coded RBL in ircd to use a sysop defined RBL list
Currently ircd uses a hard coded rbl known as dronebl to reduce spam traffic to ircd.
Suggest that dronebl is moved to a sysop configurable file of rbl's and is included as default whilst allowing the sysop to experiment with additional rbl's as required.
When blocking an IP, ircd should log which rbl caused which IP to be blocked.