reimplement Q_DISABLE_COPY_MOVE for full compatibility with versions < 5.13

I was under the impression Q_DISABLE_COPY_MOVE was a much older function than
it is. Since we historically target 5.6 and these functions are small
convenience functions, I just implemented them in the actual codebase.

app/decoder/decoder.h

@@ -22,9 +22,9 @@
 #define DECODER_H
 
 #include <QObject>
-#include <QtGlobal>
 #include <stdint.h>
 
+#include "common/constructors.h"
 #include "common/rational.h"
 #include "project/item/footage/footage.h"
 #include "decoder/frame.h"
@@ -59,7 +59,7 @@ public:
   // Necessary for subclassing, it's empty
   virtual ~Decoder();
 
-  Q_DISABLE_COPY_MOVE(Decoder)
+  DISABLE_COPY_MOVE(Decoder)
 
   virtual QString id() = 0;