Add facilitator driver model

[roncodes]

Summary

• add the missing facilitator-driver Ember Data model
• register the app re-export and driver subtype helper
• add model and maintenance schedule normalization regressions

Validation

• targeted ESLint passed for touched fleetops-data files
• focused Ember test build succeeded, but Testem failed before assertions because testem requires ESM-only execa from CommonJS in this local harness