Add Google satellite imagery option to webapp

[trinhwinn]

Like the mobile version on Android/iOS, adding the option to view Google maps such as satellite, terrain, and hybrid would bring more up to date options to the webapp for MapMarker.

[androidseb]

Hey, this was already requested here: #75, I'll paste my question from there because it was abandoned:

Unfortunately, offering Google Maps on a web app is costly - in the case of Map Marker, it would cost several thousands of dollars per month to offer this, so this is not something I will pursue for the time being.

The only viable way I could do this is by letting users who have registered their own Google Developer account with their credit card configure their own API key in Map Marker, but I'm thinking that would be a very small portion of users, and I haven't seen demand for this yet.

Would you be among those users?