As a developer,
I want to prevent accidental errors,
so that I can safely A/B test new features

Acceptance Criteria:

• There is a command added to the FundraisingFrontend console that validates the camapigns.yml file according to the following criteria:
  • The indentation is correct
  • All required parameters are present
  • The start and end dates must be quoted and in the format YYYY-MM-DD or YYYY-MM-DD H:i:s. All dates are considered to be in the Europe/Berlin timezone.
  • The end date must be after the start date.
  • The default_bucket must be part of the buckets definition.
  • Bucket names beginning with digits (e.g. 10h16) must be quoted, both for buckets and default_bucket.
  • Ensure that all buckets are unique
• The validation command is added to the CI ( ci task in the Makefile)

Background:
Basic checks for required parameters and correct structure of the file are already done by the CategoryConfiguration class.

This task is different from T196929: Create code analysis tool that checks all A/B tests are implemented, which is about checking if the code actually implements the campaigns described in the configuration file.