Update staging_pipeline_kickoff to assist with config creation when running it for the first time

Background

We can update the kickoff.py script to create the initial configuration files and add values if they don't exist.

Acceptance Criteria

• Check whether config.yaml and secrets.yaml exist
• Get content from the appropriate sample file for each file that doesn't exist
• Use input() to gather values to create each config file where appropriate
• Generate config files with provided values

Definition of Done

• All config can be provided when running kickoff script for the first time (or if config is missing)
• Consideration are made to ensure this works when:
  • out of band changes are made to the config files
  • a single file is missing