Application cloning can be used to setup review applications based on an existing application. This is useful in CI/CD pipelines where a developer may wish to verify code in a custom environment without overwriting a shared staging environment.
Since they are separate resources, triggering the normal app creation flow makes the most sense.
We still remove the cache directory because we want the correct cache permissions for the new application.
An application which has not been deployed will not have an image
available, and therefore attempting to remove an (empty) cache directory
will fail. Rather than checking for the image - which we should
still do, as not having an image for a deployed app is an error state -
we should instead only attempt the docker cache removal if the directory
cannot be removed via rmdir.
Closes#2294
