Release Environments - Build a prototype of Release Environment using GET

Context

As an exit criterion of &1567 (closed), we plan to support Geo on Release Environments, full cloud native as RE right now is not possible, because in our official doc, it is specified:

• The use of external PostgreSQL services, as the PostgresSQL included with the chart is not exposed to outside networks, and doesn’t have WAL support required for replication.

Thus, this issue aims at getting to know GET and prototyping a release environment deployed by GET.

Exit Criteria

• Demo the prototype of using GET to deploy a GitLab instance that

• Use cloud native hybrid architecture

• Use prerelease packages

• Create follow up issues to implement GET@RE