TP-1174 Created file garbage collector which removes old file entities in unused revisions

[jussiviitamaki]

Actions necessary for applying the changes: (for example composer install; drush updb; drush cim)

Testing instructions:

• lando test public/modules/custom/hel_tpm_file_garbage_collector
• Confirm tests pass
• Login and find a service which has older than 6 month old revision with files in them
• Confirm one or more files are not used is newer revision
• lando drush cron
• Confirm old files are deleted during cron run.
• Confirm used files are not deleted

Review checklist:

• The code conforms to Drupal coding standards
• I have reviewed the code for security and quality issues
• I have tested the code with the proper user roles
• I have moved the ticket to the approval lane, added testing instructions and assigned it to the product owner.