added ZyXEL GS1510-16 Password Extractor
added reference as requested at https://github.com/rapid7/metasploit-framework/pull/2709
and now in the correct data structure
added @wchen-r7's code to store the password into the database
re-added the reference I accidentally deleted
Land #2709 - ZyXEL GS1510-16 Password Extractor