Changing extensions API to separate streaming output from output_modifier

[Wojtab]

I tried Silero TTS and was annoyed that streaming output isn't shown live, so I took a look into extensions, and I seen that both SD, and TTS disable streaming during generation, as it would break them.

To fix it, I came up with an idea, to create a new hook, called for example stream_modifier, which would get called instead of output_modifier when streaming, and only when the generation has finished the output_modifier would get called. I implemented a quick&dirty POC, and added it to Silero, however the full HTML reload of the entire history on every token looked bad (for example the audio players were flashing), so I decided to separate the current message from chat history. Right now, it looks like that:

2023-04-18.03-42-51.mp4

You can try it out, by applying the following patch (on commit ac2973f): streaming.patch and then going to cai-chat (I broke the other chat modes), with just silero-tts enabled (I didn't test other extensions).

If this idea gains support, and my way of implementing it isn't completly insane, I will bring it to PR stage when I have some time.

[MotherSoraka]

Why is this not the default procedure?
and why hasnt this post hasnt gained any support?
:|