* Add documentation on how to setup GCE accounts
This commit adds the steps needed to create a credential with the needed access on Google Cloud Platform to be able to successfully create a new algo VPN.
Related to:
- https://github.com/trailofbits/algo/issues/682
- https://github.com/trailofbits/algo/issues/658
* Adds links on main README to GCP
* Adds link to Ansible documentation
* Update cloud-gce.md