Improvements to the static map layer to support updates

The current version of the static map layer does not work with dynamic updates as the costmap is not updated any more after the first map has been received. Although costmap_2d is primarily meant for static maps, there are also many use cases where the map is updated throughout the mission, e.g. for exploring unknown environments.

This pull requests contains the following updates:
* Fixed typo in `map_recieved_` variable
* Set `map_initialized_` to false in the map callback to enforce a costmap update
* Only call `layered_costmap_->resizeMap()` if the map parameters (size, resolution, origin) have changed. Otherwise the costmap would be fully reset for each incoming map.
* Changed log type for the "Received a ... map" message from INFO to DEBUG and added another one if the map parameters have changed (to not spam the console for each update).