Implement sentiment analysis core feature

[Helias]

Goals:
-- in any spot that can be analysed add a dominant emotion using an emoj
-- under any spot that can be analysed, update the "spotted by: " comment with a small report of the sentiment analysis (ex. joy, anger, positivity, negativity, fear, sadness)

check src/spotted/handlers/init.py line 138

app.add_handler(MessageHandler(community_filter & filters.REPLY, follow_spot_comment))

This will trigger the function follow_spot_comment() anytime there is a new message in the community group, so a new comment.
Based on this you could trigger a function to run the sentiment anlaysis about a specific post and comment, updating the post with the dominant emotion.

technical doubt: is it possible to retrieve all the comments having the post (spot) message_id? (I think so)

Constraint to define: what is the minimum quantity of words and/or comments in a thread to run the sentiment analysis succesfully?