Utility module for workshops

[james-jory]

Several of the workshops have code/routines that could be moved into a shared modules to improve maintainability, reusability, and streamline the workshop code.

• Copy/port rebuild_webui_service from src/aws-lambda/personalize-pre-create-campaigns/personalize-pre-create-campaigns.py so that any workshop can trigger a rebuild and redeploy of the web-ui. For example, after updating a SSM parameter value that is used by web-ui.
• The Experimentation workshops have similar/duplicate code for creating experiment configs, simulating experiments, calculating sample sizes, etc that could be factored into a module.
• The Personalization workshop has a function for generating interaction history that could be moved out of the workshop and into module.