Terraform bootstraping | Provision a leaf cluster via terraform template

[ahsayde]

Part of: #2205

• Add gitops cluster
• Create leaf cluster Terraform module
• Create Terraform template
• Created PR with the resources in the mangement git repository

[waleedhammam]

provisioned here https://github.com/weaveworks/clusters-config/pull/319/files

[waleedhammam]

TODO:

• Create a document for using TF in bootstrapping