api: quality options for screen mirroring (#313)

## Link to GitHub Issue, if one exists
n/a

## Description of change
Allow the server to override client's quality options for screen
mirroring.

On Windows / Android versions (flutter-based) clients, this is already
in the options of those apps. However, the iOS version lacks the quality
options.

## Testing
Tested with iOS and Windows clients.

src/spice2x/launcher/options.h

@@ -136,6 +136,8 @@ namespace launcher {
             APISerialBaud,
             APIPretty,
             APIDebugMode,
+            APIScreenMirrorQuality,
+            APIScreenMirrorDivide,
             EnableAllIOModules,
             EnableACIOModule,
             EnableICCAModule,