Investigate adding a `--replace` option on install

[markpollack]

With https://github.com/spring-cloud/spring-cloud-skipper/pull/194/ we can do an install over a release that was deleted. This helps support a common development workflow from the Data Flow use case perspective, but we may want to introduce an explicit --replace option as in helm in order to use this functionality vs. not allowing an install to re-use an existing release name.