Contribution access in Content hub without access to aem

[#1]

Request for Feature Enhancement (RFE) Summary:	Can we give contribution access in Content hub to our external users without giving them access to our AEM instance.
Use-case:	We have around 500 external users having their own domain email addresses, we can not give access to users with external domains to our AEM instance. We would want the external users in Content Hub to be able to upload assets without giving them access to AEM just like Brand Portal.
Current/Experienced Behavior:	To upload assets, external content hub users must have AEM access.
Improved/Expected Behavior:	External users could upload assets without having access to AEM.
Environment Details (AEM version/service pack, any other specifics if applicable):
Customer-name/Organization name:	SBR
Screenshot (if applicable):
Code package (if applicable):