Exploit command for metasploit-framework

This PR includes all changes required for https://github.com/limhoff-r7/metasploit-framework/pull/20.  It supersedes https://github.com/rapid7/metasploit_data_models/pull/51 which supersedes https://github.com/rapid7/metasploit_data_models/pull/50 which supersedes https://github.com/rapid7/metasploit_data_models/pull/49.