Add support for 'monolingual text' data type (top-level and qualifiers)
Monolingual text is a string plus a language - see https://www.wikidata.org/wiki/Property:P1684
This type of string that is not translated into other languages: it is defined once and reused in all languages. Plain text string plus a mandatory language code (IETF language tag) or a special language code. On Wikidata, special language codes are not included in the Language dropdown and must be known ahead of time or users have to know where to look to know what the special codes are (such as "unknown").
Users need to be able to add text plus language for any property that takes monolingual text as a value, in the File page and in UploadWizard
##Use cases
A monolingual text can be an official name, nickname, birth name (if different than a person’s name), an inscription, someone’s “last words” or others (see full list of Wikidata properties that use the monolingual text data type).
##User story
As a Commons editor, I want to add a string of text (as well as the language it’s in) to a media file’s metadata, so that anyone using that file can read that string and its linguistic context.
##Acceptance criteria:
[] can select a property with data type 'monolingual text' and enter a value for it
[] can add a (mandatory) language code
[] on File page
[] in UploadWizard