Multi-tenancy by table prefixes

It's an excellent introduction to multi-tenancy using EF core, but I think it lacks the approach of using table prefixes to separate the tenants. It would be nice to explain it too in the docs.

[entity-framework/core/miscellaneous/multitenancy.md](https://github.com/dotnet/EntityFramework.Docs/blob/main/entity-framework/core/miscellaneous/multitenancy.md)