This PR implements a program called `fleetctl` which scaffolds a high level CLI interface which can be used to manage a Fleet server. Configuration is articulated using an intent-based API that resembles the API that is used to configure Kubernetes clusters. The idea here is to use the Kubernetes file format as a pattern to reduce the need for operators to become too intimately familiar with dramatically different file formats. (#1578)
The launcher service implementation is an adapter around the TLS service.
All launcher methods that have an equivalent in TLS pass the business logic to the
TLS API.
Closes#1565
