Mistral CLI enhancements

I would suggest the following enhancements for Mistral CLI:

1. Instead of printing messages like "Starting new HTTP connection (1): localhost" after operations print if it was performed successfully or not.

Example:
bash-3.2$ mistral workbook-upload-definition my_wb demo.yaml
Starting new HTTP connection (1): localhost

2. Make it possible to create a workbook and upload its definition at the same time. Would it cool to have something like:

bash-3.2$ mistral workbook-create my_wb 'My deployment workflow' 'tag1, tag2' < cat my_demo.yaml

3. In case if some pre-conditions are wrong print a short message with suggestions on how to fix the problem (+ may be print standard help).

Example:
bash-3.2$ mistral
Mistral supports only v3 keystone API.

Here we should see a message that points to how we can fix the problem.

4. When printing 'mistral --help' it would be convenient to see a list of parameters for every command in brackets like:

Commands:
  complete print bash completion command
  execution-create Create new execution (workbook, task, context)
  ...