Add user comments to the generated SQL

[christophcemper]

User Story:

As an analyst
I want to use requirements tracing even into generated artifacts
get my source comment in the .erd generated into the .sql at relevant positions

Example inputs .erd

entity Person {
    person_id: int key   // [dsn->dm~virtual-pk~1]
    full_name: string key
    birthday: datetime
    age: int derived
}

should generate as .sql

CREATE TABLE Person (
	person_id int NOT NULL, 		/* [dsn->dm~virtual-pk~1] */
	full_name varchar(255) NOT NULL, 		
	birthday datetime NOT NULL		
	
	PRIMARY KEY (person_id)
);

Thereby making sure that our requirements tracing finds the tag [dsn->dm~virtual-pk~1]
referencing the design item defining that we use virtual primary keys in our data model.