settings.yaml -> conf sentiment analysis

[Helias]

check a conf implementation linked to settings.yaml and make a new one for sentiment analysis
Implement the following conf options:
-- enable/disable sentiment analysis (true/false)
-- ask or not for sentiment analysis (true/false) --> in this scenario the table sentiment_analysis_post in the db is not necessary
-- define the sentiment anlaysis constraint, examples: minimum of words/comments in a post/thread