Add a flag-based deployment create

[marclop]

Overview

Add an easy way to create deployments other than via a file definition. Much like what was proposed in #67 bounded for deployment elasticsearch create which is now defunct.

See the markdown in: https://github.com/marclop/ecctl/blob/ae757de7c7694e2160e1443bf184c69c82bf997b/cmd/deployment/elasticsearch/create_help.go

Possible Implementation

Using an intermediate structure much like the --topology-element flag in elasticsearch create with the ability to specify different resource types.

A boolean --generate-payload should be available so that the generated simplified topology can be saved into a file.

[marclop]

Moving this to MS35 since higher priority tasks will be worked in