Useful multi-tenancy resources

Some useful links in the topic:
- Deleting a Tenant
- Local testing with Cassini devserver
- 1000+ tenants
- Same site under multipe domains (kind of reverse multi-tenancy)
- Changing tenant name
- Multi-tenancy and performance
- Multiple tenants under the same domain
- Theme Override module for small tenant-level theme customizations
- And of course the relevant documentation