Rework rendering pipeline to make better use of multithreading

Move OpenGL frame to ARGB conversion to processing threads
Move video exporting to processing threads
Skip creation of BufferedImage and instead use ByteBuffer with ARGB content directly

src/main/java/eu/crushedpixel/replaymod/video/capturer/SimpleOpenGlFrameCapturer.java

@@ -0,0 +1,16 @@
+package eu.crushedpixel.replaymod.video.capturer;
+
+import eu.crushedpixel.replaymod.video.frame.OpenGlFrame;
+
+public class SimpleOpenGlFrameCapturer extends OpenGlFrameCapturer<OpenGlFrame, CaptureData> {
+
+    public SimpleOpenGlFrameCapturer(WorldRenderer<CaptureData> worldRenderer, RenderInfo renderInfo) {
+        super(worldRenderer, renderInfo);
+    }
+
+    @Override
+    public OpenGlFrame process() {
+        float partialTicks = renderInfo.updateForNextFrame();
+        return renderFrame(framesDone++, partialTicks);
+    }
+}