feat: Add add/remove button and list view about codec select in Project Settings

[kannan-xiao4]

Temporary implementation of codec selection UI in Project Setting

• Implement CodecStting control (uxml/uss/script) that notify codec setting list if change list element(add, remove, change order)

ex.

            var videoCodecSetting = rootVisualElement.Q<CodecSettings>("videoCodecSettings");
            videoCodecSetting.onChangeCodecs += codecSetting => UnityEngine.Debug.Log(string.Join(",", codecSetting));

• Add add/remove codec button
• Implement codec list view as sortable.