Enhancing virtual instructor response speed

[AKissMail]

This issue is related to updates on the LXR backend to decrease the response time for a Virtual Instructor. Currently, we use the GetAudioClip method in Unity (1) to pull audio content from the LXR repository. This method has two major limitations that drive the current design:

- It does not support POST requests, which limits the length of the question.
- It only accepts an audio file as a response. It would be useful if we could stream the audio along with the transcript of the audio.

Therefore, we need to implement an HTTP request capable of sending audio as an Audio-Byte-Stream in a POST request and retrieving both audio and transcript as JSON. This JSON should be cast into an AudioClip object and returned along with a string.

(1) https://docs.unity3d.com/ScriptReference/Networking.UnityWebRequestMultimedia.GetAudioClip.html