Refactored Activitypub_profile::ensure_web_finger to Activitypub_profile::ensure_webfinger
Do not throw exceptions in the handling of this event because we don't
want to stop the regular search just because we were unable to find
ActivityPub actors or notes.
This is not the same as the one in https://notabug.org/diogo/gnu-social-activitypub-plugin
Differences to the first "release"
-> Doesn't use guzzle nor has any composer dependencies
-> Supports HTTP Signatures
-> Has basic l10n/i18n
-> Some minor bug fixes
