Add language English to abstracts when importing from WoS

[mietcls]

Enhancement

Add language "English" to abstracts when importing from WoS.

We are going to assume that all metadata from WoS is written in English, based on the context found below. If we get negative feedback about it, we will change it.

Steps to reproduce

1. Go to https://www.webofscience.com/wos/woscc/full-record/WOS:000963572100001(overlay:export/exp) and download the publication (see attachment) savedrecs.txt
2. Go to backoffice biblio test and upload the publication https://backoffice.bibliotest.ugent.be/publication/01H2Q7F9EJ8MZPT497N0BDMRX3?redirect-url=%2Fpublication
3. See the abstract imported but the language set to unknown.

Expected behavior

As WoS expects English language bibliographic information, we can assume abstracts will be set to English.

Context

Found this information:

• _Titles of foreign-language publications are translated into English and so cannot be found by searches in the original language._
• Article titles and article abstracts in English (note: WoS requires English language bibliographic information for indexing)

[nicolasfranck]

I assume that the language is not properly set by WoS?

[nics]

@mietcls @nicolasfranck seems that we can safely set lang to eng

[mietcls]

The language is set by WoS here, which is future proof:

I'm just not sure whether that's on metadata level or on publication level.

[nicolasfranck]

There is a mapping available, which means that there are examples that do not contain a value there in the wild? Set to English when none were provided?