GDPR: Document the new JavaScript tracker methods: requireConsent, rememberConsentGiven, forgetConsentGiven, setConsentGiven

In this guide  https://developer.matomo.org/api-reference/tracking-javascript
we want to list the new methods: requireConsent, rememberConsentGiven, forgetConsentGiven, setConsentGiven
 
that were added in https://github.com/matomo-org/matomo/pull/12558
and are documented in https://developer.matomo.org/guides/tracking-javascript-guide#asking-for-consent