Add micro-region names to website (for accessibility)

Currently the user can not see (read) which micro-regions belong to a warning region, but we have the information in the XML file loaded by the website. There are two scenarios:

1. If the maps are produced correctly, we can add the names e.g. in the tooltip of the thumbnail map (but then it is not possible to see it on mobile devices. Or we can introduce a new element allowing the user to get the information.
2. If map production fails the user can see the textual information of the bulletin, but does not know which micro-regions we are talking about. Therefore we can show the micro-region names instead of the thubnail map (if loading it fails).

@rfabrizi, @TransWanner, @simon04 what do you think?