Remove low quality sources of RBL blocks
I've noticed that some messages of DNSBL don't provide enough information, or are just low quality reports, like in the screenshot below:
![image](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
They can be safely removed to remove unneeded noise in the insights view.