Localization lt

Hi all. Been working on a little project that requires Lithuanian translations, so I managed to do the first round of translations, which is a bit more filled up. I'll be adding more to this as I get more time.

I've raised this PR to 2-3-stable branch, as this is what I'm using at the moment.

Let me know if you have any questions and also bare in mind this is my first PR to Spree community :wink: