Replace use of whitelist with allowlist and blacklist with denylist

I am reading and working with Box API and I have noticed that they refer to blocklist as blacklist and allowlist as whitelist.

Considering a lot of argumentations, besides that those words are racists and we can't even use it as a verb.

Some discussions: https://twitter.com/dhh/status/1032050325513940992.

I think that Box could also follow the good exemples and replace theses terms.

Also:

> Regardless of origin, allow/deny are simply clearer terms that does not require tracing the history of black/white as representations of that meaning. We can simply use the meaning directly.
>
> _Originally posted by @dhh in https://github.com/rails/rails/issues/33677#issuecomment-414873738_

Durchsuche die Entwicklerdokumentation nach Verwendungen von „whitelist“ und „blacklist“ und überprüfe anschließend die umgebende Terminologie sowie alle verlinkten Hinweise. Erledigt ist die Aufgabe, wenn die relevante Dokumentation durchgehend „allowlist“ und „denylist“ verwendet; im Issue werden keine spezifischen Dateien oder Tests genannt.

Vom Indexierungsmodell aus dem Issue-Text verfasst.