Added Extended SMTP Open Relay aux module
Added DNS recursion amplification scanner
Changed dns_amp to avoid false positives
Added EXTENDED option to smtp_relay
removed rport definition
changes to smtp relay aux module
Module to HP LaserJet Printer SNMP Enumeration

(cherry picked from commit f18fef186462236e3fa2e23fb5269059d279174f)
fix description

(cherry picked from commit 7c860b9553be37ab958e28ca63ecd3c8d89ff4c8)
Land #2928, extended SMTP open relay checks
Land #2929, DNS recursion amplification scanner
Land #3159, HP LaserJet printer SNMP enumeration