Decouple Storage endpoint and resource definition in the resource API

[DImuthuUpe]

Currently there is no first class notion about storage endpoints. But we might need this for the storage browsing interfaces. A resource might be a child of a storage endpoint. For example: Storage endpoint will be a ssh able compute resource or a s3 bucket. Resource will be a file inside that. Storage endpoint is the one directly mapping with credentials there could be one or many credentials assigned to the storage endpoint.

[DImuthuUpe]

Fixed in 6114a77