Validates the yml and sql files for a model.
model_path: Path to model (sql or yml) to be validated.
Example output when all is ok:
Validating yml exists: yml file ok
Validating yml definition: yml file name ok
Validating yml columns: yml ok
Validating sql references: references ok
Validating sql with sqlfmt: validation ok
Validating sql with sqlfluff: validation ok