Automatically generate maps using existing internal API

[andchiind]

Describe the new feature you would like to see
There is an existing API which lets us generate png maps of Echo 3D maps, with given bounds. We should use this to automatically generate maps for missions when they are created (so that we get one map per mission definition, which is large enough to cover each tag, but not much more)

Describe the solution you'd like
We should find the bounds of the list of tags in the mission (smallest/largest x and y coordinate) and then send this to the API to generate a PNG map. This map should then be uploaded to blob storage and used in the mission. The map name in blob store can include the bounds of the image and the installation code, so that we don't need to generate a new map if one already exists.

How will this feature affect the current Threat Model?
We should use the same user permissions for this API as we do in Flotilla, so that people need to apply for access to use this feature. We should then verify this solution with Echo.