octavia-cli: import existing Airbyte resources to manage them with octavia-cli

[alafanechere]

If I created some Airbyte resources using the console (destination, source, connection), I want to be able to manage these with octavia without recreating these.

E.G.:
I want to run an octavia import source <my-source-id> command that will generate a local YAML file with the source configuration I've already set up in the Airbyte UI.