Allow disabling progress bar printing in sampling (useful for the book)

[amal-ghamdi]

General description of task

Consider printing final info. Or final progress bar

Definition of Done (Feature/change)

• description1
• description2

Definition of Done (Mandatory)

• Documentation added (docstrings on all public methods/classes)
• Unit tests added/updated (and passing!)
• Code reviewed and approved by 2 CUQI-maintainers
• Online documentation is rendered correctly (esp. math)

Definition of Done (Optional)

• HowTo/tutorial added