auto-create or at least hint that dedicated registry needs to be created for ISV registries
Description of problem:
Our Red Hat federated index (registry.access.redhat.com) shows docker search results from our ISV registries pointing to these dedicated registries (for example registry-mariadbcorp.rhcloud.com).
If our Red Hat registry has been configured as an external registry in Satellite 6 the federated index shows results from our ISV registries but if a user selects them it causes a 404 error since the registry the images lives in is not the same as configured and used.
Instead of the 404 error message we should show a hint that these ISV registries need to be configured as additional external registries including a link to the "New External Registry" page. Automatically creating the selected ISV repo as an external registry would be even better.
Steps to Reproduce:
1. Create Red Hat registry as an external registry
2. Use the New Container wizard and select the Red Hat registry
3. Search for mariadb and select the registry-mariadbcorp.rhcloud.com/rhel7/mariadb-enterprise-server repo
Error message: 404 Resource not found
Warning: The repository location is outside of the current registry. You need to configure it as an additional external registry first. Go here (Link) to configure this registry.