Hold information about platform/orchestrator in datacenters

[paveldedik]

Right now, we have the Datacenter model which stores information about the datacenter's provider, currently it can be AWS or GCP. We should also add support for holding information about platform used (e.g. Rancher, GKE/Kubernetes, etc.).

We could either add a simple field Datacenter.platform which would hold this information, but this information doesn't really belong to Datacenter. And also, it's not always THAT simple - in some environments, you can run Rancher+Kubernetes, in others you could run Rancher 1.6 which does not use kubernetes. You can also run your service without any orchestrator.

But still, this kind of matadata should be stored somewhere.