Duplicate SAP modules

modules/exploits/sap/sap_rfc_abap_install_and_run_cmd_execution.rb is a duplicate and outdated version of
modules/exploits/multi/sap/sap_rfc_abap_install_and_run.rb

modules/exploits/securestate/sap_rfc_sxpg_call_system.rb -> modules/exploits/multi/sap/sap_rfc_sxpg_call_system.rb
modules/exploits/securestate/sap_rfc_sxpg_command_exec.rb -> modules/exploits/multi/sap/sap_rfc_sxpg_command_exec.rb
modules/exploits/securestate/sap_rfc_system.rb -> modules/exploits/multi/sap/sap_rfc_abap_install_and_run.rb (merged targets)