PIM-2438 : media and file filters for the grid

Add filters on media and files

 - [x] ORM implem
 - [x] Mongo implem
 - [x] specs
 - [x] behat

| Q                    | A
| -------------------- | ---
| Bug fix?             | N
| New feature?         | Y
| BC breaks?           | N
| CI currently passes? | Y
| Tests pass?          | Y
| Scenarios pass?      | Y
| Checkstyle issues?*  | N
| PMD issues?**        | N
| Changelog updated?   | Y
| Fixed tickets        | PIM-2438
| DB schema updated?   | N
| Migration script?    | N
| Doc PR               | ~
I really have a problem with this variables names :/ Why not $fileAttribute. I know, this is not a big problem and we are in a spec so it's ok. But use long attributes name could really improve our code readability :)