Added first version of new interactive flightplan map based on openlayers

[addiks]

This adds a new interactive map for managing flight-plans. The new map widget is based on openlayers (https://openlayers.org/).

This is only the very first working version of the new map, a lot of things can still be improved, but it already allows adding, modifying and removing waypoints entirely from within the map.

The new map can be invoked with a new "Map" button in the flight view page.

[DTomas15]

Not closed due to wrong target branch. Features have been merged manually into milestone branch