Adds instructions on how to set up GKE - only docs

What does this MR do?

Adds a guide on how to create GKE clusters through Infrastructure as code.

Review app: http://main-ee-64654.178.62.207.141.nip.io/ee/user/infrastructure/clusters/connect/new_gke_cluster.html

Review details:

For the record:

Before TW CTRT review	After TW review

Related issues

#334024 (closed)

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