Adobe material in enduserids needs to move to extension schema

This schema, which is *not* an extension, refers to internal Adobe specs. As per agreement, such a schema needs to move to Adobe extensions.

## What are the schemas that are affected by the issue

https://github.com/adobe/xdm/blob/master/schemas/context/enduserids.schema.json

## What are examples of products that are impacted by the issue

Probably many, but it has to be fixed.