Better support for creation of Java Records

[gastaldi]

This should enable the creation of Java records

Example:

      final JavaRecordSource javaRecord = Roaster.create(JavaRecordSource.class)
               .setName("PhoneNumber")
               .setPackage("org.example.foo");
      javaRecord.addRecordComponent(BigInteger.class, "number");
      javaRecord.addMethod().setName("dial").setReturnType(boolean.class).setBody("return true;");

Generates:

package org.example.foo;

import java.math.BigInteger;

public record PhoneNumber(BigInteger number) {

	boolean dial() {
		return true;
	}
}

[gastaldi]

/cc @maxandersen

[maxandersen]

works! LGTM!