optionally search one language only

keep last question/answer as additional context

This should help with questions relating to the last anwser when they
haven't been rephrased well enough

option to prefer a configured language instead of guessing

Merge branch 'pineconestorage'

* pineconestorage:
implement Pinecone based storage
First go at syntax to display similar pages

use a k-means based cluster approach to speed up similarity searches

First go at syntax to display similar pages

implement Pinecone based storage

First go at syntax to display similar pages

lazy load embeddings, storage and model

This should fix an immediate problem with the sqlite db initializing
slowly, but the underlying problem has to be identified.

refactoring to make models selectable

This makes it much easier to add new models. Models can now be selected
via the configuration

Use overlapping chunks, prepare for new models

allow to restrict access to certain users and groups

added a few todos

added usage statistics

Check ACLs before using sources

Frontend integration with simple syntax component