Separate out code that applies to both standard websockets and the
future unix socket implementation.
Signed-off-by: Eric Callahan <arksine.code@gmail.com>
Add basic support "agents", ie: unmanaged extensions. Connected
agents are granted a limited ability to emit websocket notifications
and process rpc requests from Moonraker.
Signed-off-by: Eric Callahan <arksine.code@gmail.com>