Demo data and languages

[Macroz]

There is a mismatch between the languages configured for demo data and the data created for the demo data. Demo instance can have e.g. fi, en but data like titles are generated for fi, en and sv always.

• only generate test or demo data for the languages in use (i.e. parameterize by the languages) (Create test/demo data by selecting configured languages localizations #3057)
• check that you are able to edit an item that has extra translations (e.g. data with fi, sv, en and if you save it it will have only the configure languages e.g. fi, en.)

NB: there are some tickets about how the UI doesn't work so well when a language has been dropped, e.g. #2932