Disable contentRelevancy component

Bugzilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1886207

So, what is this new component? From https://phabricator.services.mozilla.com/D205266:

a client-based content relevance ranking & personalization that we want to experiment for various content surfaces such as Firefox Suggest and the New Tab page.

Unfortunately the RFC that is linked to in the comment I quote above is in a closed Google document.

Regardless, this seems like something we do not want.

From that comment it also seems it will be in "surfaces" we already disable, Firefox Suggest and New Tab, though. Prompts a review anyways.

All bugs related to this feature: https://bugzilla.mozilla.org/buglist.cgi?query_format=advanced&component=Relevancy&resolution=---&resolution=FIXED&resolution=INVALID&resolution=WONTFIX&resolution=INACTIVE&resolution=DUPLICATE&resolution=WORKSFORME&resolution=INCOMPLETE&resolution=SUPPORT&resolution=EXPIRED&resolution=MOVED&classification=Client%20Software&classification=Developer%20Infrastructure&classification=Components&classification=Server%20Software&classification=Other