rdp: Allow disabling RemoteFX codec
There are compatibility issues between FreeRDP's implementation of the RemoteFX codec and Microsoft's implementation. So it can be useful to disable it to avoid problems.
Additionally, WSLg uses RDP RAIL in a special mode that allows sharing buffers between RDP server and client on the same computer. In this use case there is no need for the RemoteFX codec at all.
Signed-off-by: Derek Foreman derek.foreman@collabora.com