Feature Request: Possibility to set list of locales

[andzno1]

I am struggling tagging my collection of German audio dramas. I got beets-audible working but it doesn't return any results for some of my German audio dramas. E.g.:

audible: Searching Audible for Der blinde Hellseher TKKG
Evaluating 0 candidates.

Entering that exact search term on the German audible page (audible.de) yields a result though:

while entering the same search term on the US page (audible.com) doesn't yield any result:

Therefore it would be a really nice feature to be able to configure the plugin similar to beets' import.languages setting, e.g:

audible:
  languages: de en

That new setting would enable us to provide a list of language locales making it possible to query different audible endpoints in order of the given list.

[peterpiglet]

this functionality would be awesome!