Stop assuming that our render pipeline will only process RGB frames

For one, we have already switched to RGBA some time ago, so the name was
technically incorrect already.
But the main reason is that we'll want to use them for depth maps as well (and
potentially maybe even for HDR images if that's possible with canvas?).

src/main/java/com/replaymod/render/gui/GuiVideoRenderer.java

@@ -1,7 +1,7 @@
 package com.replaymod.render.gui;
 
 import com.replaymod.core.utils.Utils;
-import com.replaymod.render.frame.RGBFrame;
+import com.replaymod.render.frame.BitmapFrame;
 import com.replaymod.render.rendering.VideoRenderer;
 import de.johni0702.minecraft.gui.GuiRenderer;
 import de.johni0702.minecraft.gui.RenderInfo;
@@ -265,7 +265,7 @@ public class GuiVideoRenderer extends GuiScreen implements Tickable {
         guiRenderer.drawTexturedRect(x, y, 0, 0, width, height, videoWidth, videoHeight, videoWidth, videoHeight);
     }
 
-    public void updatePreview(RGBFrame frame) {
+    public void updatePreview(BitmapFrame frame) {
         if (previewCheckbox.isChecked() && previewTexture != null) {
             ByteBuffer buffer = frame.getByteBuffer();
             buffer.mark();