Nested repositories support in Quay

Customer Problem:

As a Quay user I like to push content with arbitrarily nested namespace designations. Sometimes I do not have control over this when mirroring or mass importing content from another registry. Other times I like to provide hierarchical structuring to my content to users can more easily discover what is interesting to them.

Goal: Nested repositories support in Quay

Problem:

• as of today Quay uses registry namespaces as organizations and user namespaces and allows repositories underneath. There isn't any capability to group repositories even further.
• the current model isn't well aligned to OpenShift projects
• the current model forces Quay users to workaround the tenant concept of Quay via org's
• external scripts / apps such as the OCP mirroring scripts require / expect nested repos
• other registries feature nested repositories already today

Why is this important: 

• Extends the value of OpenShift using Quay
• Extends the value of Quay if used in conjunction with OpenShift
• provides additional flexibility to end customers and better supports large customer org's and deployments

Dependencies (internal and external):

• nested repo support breaks v1 support and therefore our long-term spec commitment

Prioritized epics + deliverables (in scope / not in scope):

• As a user I can create and use structures like <my_registry_host>/<my_quay_org>/<my_project>/my_repo>:<tag>
• As a user I can select whether I want to use docker v1 legacy support which conflicts with the (enabled by default?) nested repo support in Quay

Estimate (XS, S, M, L, XL, XXL):  TBD

Previous Work: 

• TBD

Open questions:

• alternative ways to achieve the same goal of sharing permissions and templates with more than an org?
• transition from current model to new model in an automated fashion feasible?