Refactor: AudioListener reduce object allocations

[capdevon]

Reduce object allocations when ALAudioRenderer update listener each time the Camera is moved:

This pull request refactors the Listener class in the jMonkeyEngine audio system. The main changes include initializing the location, velocity, and rotation fields at declaration instead of in the constructor, removing redundant constructor assignments, and introducing reusable Vector3f instances (left, up, direction) for direction calculations.

Methods that return direction vectors now store results in these fields rather than creating new objects, improving memory efficiency and reducing unnecessary allocations. Overall, the changes streamline object management and optimize performance in the Listener class.

https://github.com/jMonkeyEngine/jmonkeyengine/blob/master/jme3-core/src/main/java/com/jme3/audio/openal/ALAudioRenderer.java#L768

    private void applyListenerRotation(Listener listener) {
        Vector3f dir = listener.getDirection(); // <--
        Vector3f up = listener.getUp(); // <--
        // Use the shared FloatBuffer fb
        fb.rewind();
        fb.put(dir.x).put(dir.y).put(dir.z);
        fb.put(up.x).put(up.y).put(up.z);
        fb.flip();
        al.alListener(AL_ORIENTATION, fb);
    }