View source for Tenants and users definition

* Tenants PaaS (creator)
** Represents an entity that will create monitoring services to be published in the marketplace. It defines thing and observation types involved in the service
** A new tenant PaaS is created when a new user is registered with the role Creator

* Tenant SaaS (follower)
** Represents an entity, could be a company, that will consume different services from the marketplace, and will pay for them.
** A new tenant SaaS is created when a new user is registered with the role Creator
** Users invited to the tenant consume '''all''' the services the tenant is subscribed to, according to the access control policies (actors) assigned to the user. 

* For all tenants, PaaS and SaaS
* There is a fixed cost per tenant
* Multiple users can be invited to the tenant, without any extra cost

* Users
** Can be creators, follower admin or invited followers