This change moves all the personas code into its own module. We want to treat them as a building block features can built on top of, same as `Completions::Llm`.
The code to title a message was moved from `Bot` to `Playground`.
Previous version was prone to the bug:
https://github.com/ruby-concurrency/concurrent-ruby/issues/1075
This is particularly bad cause we could have a DB connection
attached to the thread and we never clear it up, so after N hours
this could start exhibiting weird connection issues.
The custom field "discourse_ai_bypass_ai_reply" was added so
we can signal the post created hook to bypass replying even
if it thinks it should.
Otherwise there are cases where we double answer user questions
leading to much confusion.
This also slightly refactors code making the controller smaller