Support different package layouts in Acceptance Test Sandbox #824
Description
Currently, everything in the Sandbox for acceptance tests uses hard-coded paths. This makes things difficult when dealing with migrations, as it requires tests to manually verify directory structures. We should instead update the sandbox to support the versioned layouts so that a test can specify directly which version should be used when creating the sandbox. This will allow us to simplify the sandbox by delegating to the layout struct while at the same time supporting multiple layout simultaneously.