Migrate data centers to hosting providers

[tortila]

We want to get rid of the notion of "Datacenter" from our system.

The migration process is as follows: for each datacenter, create a new hosting provider with 1 location. Tag the newly created hosting provider to know to which provider the datacenter was pointing to (this information can be useful when we enable the notion of a supply chain in the system). The newly created hosting provider should be configured as offering colocation services (to be confirmed).

[tortila]

Migrate data centers to hosting providers

[tortila]

It seems to me that we would benefit from taking on this task only after #335 is done. Currently there's a foreign key from User to Hostingprovider. If we were to migrate the Datacenters to Hostingproviders, we would end up with a bunch of Hostingproviders without any users assigned to them.

Additionally, Justine raised an important point, that some of the Datacenter objects in the system are not "real" data centers, but rather a way for hosting providers to express that they offer colocation services. If we create new Hostingprovder object out of every Datacenter object, we might introduce duplicated hosting providers. @mrchrisadams do you have any ideas about this?

[tortila]

Here's what we agreed on with Chris yesterday:

• we don't want to delete the data centers from the databse. Let's mark them for deletion now and perform it after some time (months), when we're sure we migrated all the needed data
• some data centers have city assigned, we should retrieve it when creating a new location
• if there's any evidence attached to the data center, this should be linked to a corresponding hosting provider and marked as private