Initial commit of modules for NTP vulns described in R7-2014-12

Not entirely functional or polished, but mostly working
Gut admin functions from R7-2014-12 NTP modules

None of these are admin modules.  All of that stuff should eventually go
in auxiliary/admin
Return the NTP message, not the string
Add new mixin for helping to detect DRDoS vulns
Update R7-2014-12 NTP modules to use new DRDoS mixin
Move rdoc for Msf::Auxiliary::DRDoS
Add rspec coverage for Msf::Auxiliary::DRDoS
Fix 'domain\user' reporting in mremote
Allow singular NTP version and mode 7 implementation testing
Update ntp_monlist to use UDPScanner, NTP and DRDoS mixins
Only discard monlist replies that are impossibly short

This fixes the case where if a monlist reply only includes one peer
Store peer data note in the same format as originally
If a peer is 127.0.0.1, don't try to store it because we (currently...) can't
IP Board Login Scanner Module
Fixed targeturi value
Removed function no longer used
Updated module based on feedback
Changed keyword used when returning
Updated module based on feedback
Land #3645, @jlee-r7's fix for mremoge credentials gather module