Support new esri basemaps as default map service connection in Geocortex Essentials

The ability to use Esri Basemaps has been a staple of GE for years. This has been true as the requirements have changed to include things like vector basemaps and the requirement to communicate over TLS 1.2. I'm hopeful this can be true for the new vector basemaps too.

I know there's a next gen tool that will sunset GE, but it's not a full parity yet. There are still plenty of GE sites out there, so I'm hopeful VertiGIS can continue to support them as the transition continues.