RRG should support the [`ListProcesses`][ps-action] action. It does not have any input arguments and should respond with [`Process`][ps-response]. [ps-action]: https://github.com/google/grr/blob/f0c26b1e83e77a8f53f7b7aef706b418061682ae/grr/client/grr_response_client/client_actions/standard.py#L411-L421 [ps-response]: https://github.com/google/grr/blob/f0c26b1e83e77a8f53f7b7aef706b418061682ae/grr/proto/grr_response_proto/sysinfo.proto#L91-L124