LOK may get way too many languages if there are dictionaries for them
installed which blows the pre-init to >2G easily; let's allow limiting that.

Also make the preloading of languages work with the internal spell checking
dictionaries and thesauri.

Change-Id: I77119970030a7386a5cccbe4fdc89b15eab56ef1
Reviewed-on: https://gerrit.libreoffice.org/48722Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Michael Meeks <michael.meeks@collabora.com>