Usage stats collection

[svilens]

It would be useful to collect usage stats for each user action, e.g. for each autocomplete suggestion to collect maybe the prompts/suggestions and whether the suggestions have been accepted, so that ultimately the acceptance rate can be calculated.

This is also applicable to the chat - thumbs up/down or a response rating button can be introduced and the usage of that button can also be collected, so that ultimately response satisfaction rate can be calculated.
Ideally, there could be an endpoint to where all these statistics to be sent.