graphics: option to change primary monitor before launching game (#608)

## Description of change

Adds `-mainmonitor` option which changes the monitor layout before
launching the game. This is much more reliable than the old `-monitor`
option which operated at DX9 level. This works for TDJ/UFC subscreens,
for example.

Rename `-monitor` option to `-dx9mainadapter` to discourage use.
`-monitor` will continue to work, of course.

Changing of primary monitor happens first before any orientation changes
/ refresh rate changes, which means those options will result in the
logically correct configuration.

Create a new option category for `Monitor` (rotate, refresh rate, etc).

Add a monitor selection widget for `-mainmonitor` option in the
configurator.

Improve how we log names of monitors in the log during boot - should be
less of "Generic PnP Monitor" after this.

src/spice2x/util/sysutils.h

@@ -1,10 +1,18 @@
 #pragma once
 
 #include <string>
+#include <vector>
 #include <cstdint>
 
 namespace sysutils {
     void print_smbios();
     void print_gpus();
     void print_os();
-}
+
+    struct MonitorEntry {
+        std::string display_name;  // \\.\DISPLAY1
+        std::wstring friendly_name; // Dell S2204T; wstring so that it can be converted to utf8 or string
+    };
+
+    const std::vector<MonitorEntry> &enumerate_monitors();
+}