This epic is to cover support for the use case of multi-tenancy using multiple control planes within the same cluster. This will NOT be the same feature as Maistra's "multi-tenant" feature, but a simplified multiple control plane topology with some degree of isolation between tenant data planes, while control planes continue to be cluster scoped. 

An "Experimental" feature exists upstream to support this topology: https://istio.io/latest/docs/setup/install/multiple-controlplanes/ using revisions and discoverySelectors. This epic is to bring this feature to a point that it can be supported as generally available, and to consider enhancements to improve isolation and ease of setup.

a) Work with the community to bring this feature out of its experimental status, and then:

a) Document the multi-control plane feature as is.

b) Look for opportunities to enhance the use case - e.g. multiple namespace isolation, easier setup with the sail operator, etc.