User must be able to toggle Grid (coordinates)

[tejl]

When creating a search and rescue operation it is often necessary to add a grid to the view to validate if coordinates, etc are correct. Also to be able to plan the search and rescue operation.

This toggling of a grid should be done independently of search and rescue functionality, as it may be usable in other scenarios. It may be a good idea to add the toggling to the map controller in the upper right corner.