feature: add ABM admin cluster script

[Shabirmean]

Fixes #458

Description

• We need a new bash script for setting up GCP and creating a ABM admin cluster
• This script will be used as a prerequisite for creating user cluster via UI

Change summary

• Add new script for the admin cluster creation
• Reorganize docs to explain the different scripts in this sample's folder
• Renamed the old setup_and_install_abm.sh script to install_hybrid_cluster.sh; however the old cluster is kept as is to make sure the docs referring to it don't break. Once the references are updated to point to the new script we can remove it

Related PRs/Issues

• N/A

[snippet-bot]

Here is the summary of changes.

You are about to add 20 region tags.

• anthos-bm-gcp-bash/install_admin_cluster.sh:42, tag anthos_bm_gcp_bash_admin_create_sa
• anthos-bm-gcp-bash/install_admin_cluster.sh:52, tag anthos_bm_gcp_bash_admin_enable_api
• anthos-bm-gcp-bash/install_admin_cluster.sh:72, tag anthos_bm_gcp_bash_admin_add_iam_role
• anthos-bm-gcp-bash/install_admin_cluster.sh:112, tag anthos_bm_gcp_bash_admin_vms_array
• anthos-bm-gcp-bash/install_admin_cluster.sh:127, tag anthos_bm_gcp_bash_admin_create_vm
• anthos-bm-gcp-bash/install_admin_cluster.sh:151, tag anthos_bm_gcp_bash_admin_check_ssh
• anthos-bm-gcp-bash/install_admin_cluster.sh:166, tag anthos_bm_gcp_bash_admin_add_vxlan
• anthos-bm-gcp-bash/install_admin_cluster.sh:193, tag anthos_bm_gcp_bash_admin_init_vm
• anthos-bm-gcp-bash/install_admin_cluster.sh:222, tag anthos_bm_gcp_bash_admin_add_ssh_keys
• anthos-bm-gcp-bash/install_admin_cluster.sh:237, tag anthos_bm_gcp_bash_admin_install_abm
• anthos-bm-gcp-bash/install_hybrid_cluster.sh:20, tag anthos_bm_gcp_bash_hybrid_create_sa
• anthos-bm-gcp-bash/install_hybrid_cluster.sh:30, tag anthos_bm_gcp_bash_hybrid_enable_api
• anthos-bm-gcp-bash/install_hybrid_cluster.sh:50, tag anthos_bm_gcp_bash_hybrid_add_iam_role
• anthos-bm-gcp-bash/install_hybrid_cluster.sh:90, tag anthos_bm_gcp_bash_hybrid_vms_array
• anthos-bm-gcp-bash/install_hybrid_cluster.sh:106, tag anthos_bm_gcp_bash_hybrid_create_vm
• anthos-bm-gcp-bash/install_hybrid_cluster.sh:129, tag anthos_bm_gcp_bash_hybrid_check_ssh
• anthos-bm-gcp-bash/install_hybrid_cluster.sh:144, tag anthos_bm_gcp_bash_hybrid_add_vxlan
• anthos-bm-gcp-bash/install_hybrid_cluster.sh:171, tag anthos_bm_gcp_bash_hybrid_init_vm
• anthos-bm-gcp-bash/install_hybrid_cluster.sh:200, tag anthos_bm_gcp_bash_hybrid_add_ssh_keys
• anthos-bm-gcp-bash/install_hybrid_cluster.sh:215, tag anthos_bm_gcp_bash_hybrid_install_abm

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment