Move create cluster Vue apps to create_cluster directory.
What does this MR do?
It creates a create_cluster
directory to collect Vue applications to create Kubernetes clusters in different cloud providers. It also moves gke_cluster_dropdowns application to the aforementioned directory.
Why?
A better naming structure will make easier to discover Vue applications related to create and manage K8 clusters.
This MR is part of the development plan to deliver https://gitlab.com/gitlab-org/gitlab-ce/issues/46686