1.15.3

[mbecker20]

• Env variable / volume / port parser supports single quote (') wrapped value
• Add toggle to return to behavior of recloning stack every time.
• Fix for Gitlab compatibility - Requires Periphery update
• Support Stack pre deploy shell command
• Deployments can configure registry account to log in with for private images
• When you only have one server, new Stacks / Deployments will auto assign it to the single server.