Blueprint validation

Invalid blueprints can be submitted into the db, when adding a new pipeline. Invalid blueprints can cause internal server errors. There schould be a validation on the content of the json submitted as the blueprint. (Check for "phases" and "id", "name" in the individual steps)

Minimal Blueprint:

{
    "phases": [
        [
            {
                "id": ...
                "name": ...
            }
        ]
    ]
}