hle: Eliminate need to specify command headers for IPC.

[Steveice10]

• RequestParser now uses the header from the command buffer to parse the request instead of requiring the ID and parameter counts to be passed in manually.
• FunctionInfo now only requires the command ID instead of the full command header. There is never a case where we need to match on the full header; command IDs are always unique for a service.
• Removes specialized templates in CFG and NWM services for commands reused with multiple IDs, since they are no longer necessary with these changes.

Did some basic tests with the home menu and some games, everything seems to work as expected. Most of the changes here are just find-and-replace removing parameters from parsers and pulling the IDs out of function table headers.

---

This change is