Reduce load time for the CLI client

[berggren]

This PR refactors how we do imports in the CLI client. The current implementation has some slow imports (the API client with cloud dependencies etc). The way Click works is it imports all commands at startup.

By moving the imports in the commands to inline with the function we lazy import when needed. This speeds up the UI significantly.

I also refactored the state object, moving initializing the API client and config assistant to properties instead, with the ability to cache the objects (for commands that access them multiple times).

These changes reduced time to load the tool from ~1.4s -> ~0.2s. Making the tool much snappier to use.

• Further more, some cleanup of help messages, and the renaming of import to upload to make it more intuitive.