Rework Windows launchers:

- Use SDL2 message boxes instead of Winforms.
- Use a proper project instead of compiling a single file.
- Use assembly attributes instead of modifying strings in the source code.
- Remove generic OpenRA.exe launcher.
- Replace MakeLAA.exe with a python script.

packaging/windows/MakeLAA.py

@@ -0,0 +1,19 @@
+# Copyright 2007-2020 The OpenRA Developers (see AUTHORS)
+# This file is part of OpenRA, which is free software. It is made
+# available to you under the terms of the GNU General Public License
+# as published by the Free Software Foundation, either version 3 of
+# the License, or (at your option) any later version. For more
+# information, see COPYING.
+
+import struct
+import sys
+
+if __name__ == "__main__":
+    print(sys.argv[1] + ': Enabling /LARGEADDRESSAWARE')
+    with open(sys.argv[1], 'r+b') as assembly:
+        assembly.seek(0x3c)
+        peOffset = struct.unpack('i', assembly.read(4))[0]
+        assembly.seek(peOffset + 4 + 18)
+        flags = struct.unpack('B', assembly.read(1))[0] | 0x20
+        assembly.seek(peOffset + 4 + 18)
+        assembly.write(struct.pack('B', flags))