Configurable automatic cleanup for Successful AppWrappers

[dgrove-oss]

Consider adding configurable automatic cleanup after completion of an AppWrapper.

Can draw inspiration from similar feature on Jobs (https://kubernetes.io/docs/concepts/workloads/controllers/job/#ttl-mechanism-for-finished-jobs).

We may want to have different default behavior for successful vs. failed jobs.

[dgrove-oss]

For failed jobs, this was done in #71.

For AppWrappers that end in the Succeeded state we follow MCAD and do not delete the resources until the AppWrapper itself is deleted. It would be fairly easy to add automatic deletion in the Succeeded state (after a fairly long time period, as a Succeeded AppWrapper has no pods and therefore is not consuming significant resources).