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.
As an aside, it's also generally better to make use of the [newer logging format](https://www.mediawiki.org/wiki/Manual:Logging_to_Special:Log#1.19_and_later) than the older method [currently being used](https://github.com/Wikia/app/blob/245a7765/extensions/wikia/WikiaInteractiveMaps/models/WikiaMapsLogger.class.php#L59-L73).