[wip] websocket streaming api

[one-some]

not ready for merge, just putting it here so i dont get bored of it, forget about it, and start over for the 3rd time :P This'll be nice for external projects that dont want to wait for 1.428 quintillion years to see some letters, especially external UIs

• adds websockets dependency (todo: add to dep files)
• adds a websocket server hosted on port 4999 (todo: allow custom port via cli). as of now, this supports raw_generate with no metaparameter control.
• adds a token_callback parameter to raw_generate
• toys around with an ai.py file for storing global references to model stuff to prevent cyclic imports (since aiserver is bigbigbig). might take a shot at moving load_model/unload_model and similar stuff there as well. could rename this to kai.py and store things like arguments there as well, since the utils.args hack used in the modeling directory is a really yucky hack

[henk717]

I'd love to see your SSE PR, but for now since we already decided we are not going the websockets API route ill close this for now.