Tungsten Fabric deployment prerequisites

Before you proceed with the actual Tungsten Fabric (TF) deployment, verify that your deployment meets the following prerequisites:

Your MOSK OpenStack cluster is deployed as described in Deploy an OpenStack cluster with the Tungsten Fabric backend enabled for Neutron using the following structure:
```
spec:
  features:
    neutron:
      backend: tungstenfabric
```
Your MOSK OpenStack cluster uses the correct value of features:neutron:tunnel_interface in the openstackdeployment object. The TF Operator will consume this value through the shared secret and use it as a network interface from the underlay network to create encapsulated tunnels with the tenant networks.
Considerations for tunnel_interface
- Plan this interface as a dedicated physical interface for TF overlay networks. TF uses features:neutron:tunnel_interface to create the vhost0 virtual interface and transfers the IP configuration from the tunnel_interface to the virtual one.
- Do not use bridges from L2 templates as tunnel_interface. Such usage might lead to networking performance degradation and data plane downtime.
The Kubernetes nodes are labeled according to the TF node roles. For the complete list of node roles and their Kubernetes labels, see Node roles and labels.