Intro tutorials for MCS API use cases

Develop some vendor agnostic intro tutorials about the MCS API that can be easily digested as part of a generic documentation push. Keep them implementation agnostic but I think it would be useful to tie them to some common use cases as suggested below.

Ideas:

• MCS for a single-cluster stateful service serving multiple clusters (single ServiceExport case) (see this walkthrough for some inspo)
• MCS for a same-named stateless service in clusters in different regions for simple failover (merged ServiceExport case)
• MCS for a same-named stateless service for blue-green upgrade (see this video for example)