Use -- skip-integration flag when installing ManagedConcourseServer

[jtnelson]

The ete test framework should use the skip-integration flag when installing the managed concourse server. Right now, the framework doesn't use the flag and employs a hack where it kills the installer process after 1 second in order to avoid hanging on waiting for the admin password.

Its possible the logic will need to check if the version >= 0.5.0 before trying to use the flag.