Display what other language versions of a document are available

[RafaPolit]

Since we developed a 'fallback' document system, its not always clear if there are different versions of a particular document.

There are times when you want to see / know if the instance has a particular language of a particular document without actually changing the UI language.

For that, it would be useful to hold, underneath the 'document' section of Document View, a list of what 'other' language versions of the same PDF are available and have them ready for download.

As a nice to have, you could click on a particular language version and render that PDFs version in the viewer without actually changing the UI language.

[txau]

More over, along with this we should tweak the way Uwazi is presenting the documents so that users can see the document in one language regardless of the UI interface.

[txau]

Same as: #2070

[txau]

Fixed in #2070