Collect: GEO: Add map settings for custom tile service

[jnordling]

[wonderchook]

This would be very useful. In one of our projects I found out people were using OpenStreetMap tiles instead of satellite imagery we provide because they could zoom around and cache some tiles before being disconnected to the internet. For the specific satellite imagery we were using they would need to use GeoODK and also create MBtiles.

[lognaturel]

@wonderchook very interesting and great to have a specific use case to design and build this feature for.

Can you tell us what the service you've been using for that imagery is?

[wonderchook]

We provide DigitalGlobe's MapAPI imagery. I could also see wanting to add other tile services, sometimes we work with groups that have tiled drone imagery as well. 

[jnordling]

Ill take this one. I have been wanting to add this for awhile. Ill have to think about it via ODK core structure. I thinking at the map setting level add a config your online use of a tile layer.

[jnordling]

[lognaturel]