PIM-2262 : move the generateFilenamePrefix method

| Q                    | A
| -------------------- | ---
| Bug fix?             | N
| New feature?         | Y
| BC breaks?           | N 
| CI currently passes? | Y
| Tests pass?          |  Y
| Scenarios pass?      | Y
| Checkstyle issues?   | N
| Changelog updated?   |  N
| Fixed tickets        | PIM-2662 (partially)
| Doc PR               |