Mdm::Host#address IPv4 CIDR, Range, and address search

[MSP-10033](https://jira.tor.rapid7.com/secure/RapidBoard.jspa?rapidView=84&selectedIssue=MSP-10033)

Search `Mdm::Host#address` using the `address` operator, which can searching using the CIDR (address/prefix_length), Range (address-address) or single address format.
I will remove the duplicate section cmment, but...

The comment isn't necessarily for you or me (although I do like it).  It's to call out that other devs should be grouping together similar calls, DSLs, etc.    It follows the the same convention as calling out the section for associations.  If you don't think that's necessary, I would have to disagree.  Other devs on the team have had very slopping class layouts and in the past not organizing my sections explicitly has led to associations, validations, or methods being double declared (although sorting everything by name in a given section helps with that too), which can lead to frustration as you waste hours trying to figure out why your method override change isn't working and it's actually because there's two versions of the method in the class.