Fix EZP-22095: eZ Star Rating does not work for anonymous

Link: https://jira.ez.no/browse/EZP-22095

## Description
Since we added an antispam feature in 4.1, using star rating for anonymous user was not working anymore. This patch reintroduce the anonymous rating by using a new setting that bypasses the spam feature (some user might be in a spam free environment such as some intranets). It also makes sure to create sessions only when needed.

## Tests
Manual tests