Interactive maps messages review

This pull request was created only for message review purposes. Do not merge it!

Dear ComEng developers: pick red or green background to review the messages and their documentation, please :)

Once you finish review and we address all found issues we'll be able to delete the branch.
I've just changed "then" to "than". The parameters' handler is [built-in in our validators](https://github.com/Wikia/app/tree/dev/includes/wikia/validators). I probably can change it to more MW style like `$1` and `$2`... Do you have any other suggestions?