Smooth transition for VideoView capture position update (#383)

When capture position update is detected:
1. Creates a secondary renderer view in the back of primary renderer
2. Renders some frames (2 frames) on secondary renderer
3. Executes animated primary secondary renderer swap
4. Sets rendering back to primary renderer

- [x] Ensure clean up
- [x] Add animation preference properties

<table>
    <thead>
        <tr>
            <th align="center">Before this PR</th>
            <th align="center">CrossDissolve</th>
            <th align="center">Flip</th>
        </tr>
    </thead>
    <tbody>
        <tr>
<td align="left"><video
src="https://github.com/livekit/client-sdk-swift/assets/548776/fc2a95c1-c77a-4e67-a798-97e77867f8d7"
controls="controls" style="max-width: 730px;"></video></td>
<td align="center"><video
src="https://github.com/livekit/client-sdk-swift/assets/548776/4c025cbe-028c-46f3-9154-8349e3c35224"
controls="controls" style="max-width: 730px;"></video></td>
<td align="right"><video
src="https://github.com/livekit/client-sdk-swift/assets/548776/20914b2e-ffa2-4420-8307-2a33b61d463f"
controls="controls" style="max-width: 730px;"></video></td>
        </tr>
    </tbody>
</table>

Author: hiroshihorie

Sources/LiveKit/Support/NativeView.swift

@@ -64,6 +64,10 @@ open class NativeView: NativeViewType {
     public func bringSubviewToFront(_ view: NSView) {
         addSubview(view)
     }
+
+    public func insertSubview(_ view: NSView, belowSubview: NSView) {
+        addSubview(view, positioned: .below, relativeTo: belowSubview)
+    }
     #endif
 
     open func performLayout() {