Allow Field Maps to have it's own custom Basemap Gallery

[RhettZufelt]

Allow Field Maps to have it's own Basemap Gallery like they did with Survey 123. (more info here ) 

The majority of cases with field collection, one or two basemaps should do, not the entire collection available to the organization.

I would like to have online Field Maps that only show my selected Basemap that are relevant to the current project, not the 20 plus choices that come up by default (either ArcGIS Online gallery, or custom basemap gallery). 

Survey 123 now has that capability, but it is just as relevant, maybe more for Field maps as well.

R_