Allow changing Unity Apple Build Settings in Windows Editor

[michaelclockstone]

Now the Apple Build Settings only show up in MacOSX Editor under Project Settings. Please support editing those settings in the Windows Editor too as we are using Windows PCs for development and building is only done in the cloud respectively build servers that run on OSX.
Thanks!

[michaelclockstone]

Even better would be if building the XCode project would also be possible from within the Windows Unity Editor which should be possible, however many #if UNITY_EDITOR_OSX checks prevent that.