chore: Set statement timeout for Postgres (#6641)

By default, Rails does not set a timeout on database statements. For example, this will run for a full day, even if your ruby process goes away. But it's configurable in the database.yml with the statement_timeout variable.

Hence we are enforcing a 14s timeout by default. Migration commands inside chatwoot will run with a 10 minutes timeout. For specific cases like migrations, we can override this timeout using the environment variable POSTGRES_STATEMENT_TIMEOUT while starting a new rails console.

Test the timeouts from the rails console using.

```
ActiveRecord::Base.connection.execute("SELECT pg_sleep(15);")
```

ref: https://github.com/ankane/the-ultimate-guide-to-ruby-timeouts#postgresql
ref: https://til.hashrocket.com/posts/b44baf657d-railspg-statement-timeout-

Procfile

@@ -1,3 +1,3 @@
-release: bundle exec rails db:chatwoot_prepare
+release: POSTGRES_STATEMENT_TIMEOUT=600s bundle exec rails db:chatwoot_prepare
 web: bin/rails server -p $PORT -e $RAILS_ENV
 worker: bundle exec sidekiq -C config/sidekiq.yml