[tma2] [Ongoing] Continue implementing modules for tma2. (#1388) ...

* cs: add stub sysmodule to host command shell server

* cs: implement logic for main (linker error paradise, for now)

* cs: implement more of the system module's skeleton

* htcs: update client type names for libnx pr merge

ams: implement socket api for htclow socket driver

htc: implement socket driver (socket api not really impl'd yet)

htc: implement htcmisc service object commands

htcs: implement rpc tasks

htcs: hook up HtcsService to rpc client

htcs: fix magic template argument deduction, do Close/Connect/Bind

htcs: hook up CreateSocket/RpcClient Begin<>/End<>

htcs: hook up manager impl to (unimplemented) service

htcs: hook manager up to (unimplemented) manager impl

htcs: hook service objects up to (unimplemented) manager apis

htc: Implement (almost) all host-directory commands

htcfs: implement OpenDirectory/CloseDirectory

htc: implement htcfs protocol bringup

htclow: add Channel wrapper class

htc: Implement RpcClient::ReceiveThread + SendThread

htc: add RpcTaskQueue/RpcTaskIdFreeList

htc: implement htcmisc rpc tasks

htc: implement mux side of connecting (and more)

htc: declare and begin impl of HtclowManagerImpl interface

htc: implement HtclowDriver

htc: implement remaining worker thread send logic (for channel mux)

htc: add remaining worker receive thread logic

htc: implement service channel parsing (ReceiveReadyPacket)

htc: implement much of worker receive logic

htc: implement htclow listener thread

htc: implement complete usb driver

htc: implement (fixing linker errors) through HtclowManagerImpl::OpenDriver

ams: bump version to 0.18.1

usb: add ds client api