Add code health warning documentation for the kludgy workaround for the HERE API's lack of custom base map support
Provide a default implementation of this.defaultBaseMaps in mxm.core.js for each provider specific implementation to override/populate. Modify initBaseMaps() to check that this array has been populated correctly.
Add default core this.defaultBaseMaps implementation to the new provider template source file.
Update the Google, HERE and Leaflet implementations to use the new core defaultBaseMaps array and the updated initBaseMaps() method.
Update the autoload definitions for HERE to use the latest (2.5.3) API version and migrate the authentication code for HERE to use the new app_id and app_code settings.