support set monitor info and scale

[okhowang]

relate neutrinolabs/xrdp#1692

use client info set parameter for xorg.

many window managers have different scale setting method.
see https://wiki.archlinux.org/index.php/HiDPI .
It seems that cannot adapt for all wm.

and there is no other multi monitor dpi solution except https://askubuntu.com/a/555812
but it will break layout of monitors. because it will change resolution of monitors.

so I don't process scale in this PR.

[okhowang]

I found use xf86SetApi can set global dpi for X system.
but It didn't work if I call it in rdpRRSetRdpOutputs.
can we load client_info earlier for compute dpi in rdpPreInit

[Nexarian]

We already call xf86SetDpi here:

xorgxrdp/xrdpdev/xrdpdev.c

Line 244 in a4ce59b

xf86SetDpi(pScrn, 0, 0);

As to the right place to call it to make it work for client info, I'm not yet sure. We should play with it. I've also shameless copied your code here: https://github.com/Nexarian/xorgxrdp/pull/new/dpi_resizing_prototype so I can play with it. It is rebased off the latest devel branch.

@jsorg71 Do you know where we should put xf86SetDpi for screen resizing purposes? We should also pay attention to this for LRandR use-cases.