Add oobabooga text generation webui api completer

[kabachuha]

Connects to local models: LLaMa (including llama.cpp), local GPT-derivatives via oobabooga's text generation webui

Closes #11

[rizerphe]

Just opened this; will see what I can do in the meantime

[kabachuha]

Yes, thanks! @rizerphe . It was a real problem

[rizerphe]

Just opened this as well; currently working under the assumption that my changes get accepted

[rizerphe]

Overall this seems to be working for me; I hope the generation web UI gets CORS support; other than that the only real problem left seems to be model switching - I don't like the idea of it in general, and I don't like how clumsily I had to do it even more.

Oobabooga only allows you to have one model loaded at a time, and switching takes a lot of time, and this isn't too convenient. For now, what I do is before every generate call, I check which model is loaded (through another API call) and load the one I need if necessary. Doing it differently could be smarter but requires a bit of a rewrite.

[rizerphe]

Quickly wanted to mention that oobabooga merged my pull request, therefore you don't need to use my fork anymore.