Full pipeline support for GitOps

[BSick7]

Overview

Nullstone provides GitOps support for preview environments through pull requests. However, those configurations don't have an effect on pipeline environments once a PR is merged. Adding support includes two major improvements:

1. Nullstone will synchronize blocks that are not apps (e.g. datastores, clusters, networks, etc.)
2. Nullstone will perform GitOps synchronize on pipeline environments.

How will it work?

WIP:

• Per-branch synchronization (like deploys)
• Approval workflow