[FEATURE] Updated to order by [sulu:order] by default

This PR will make the FilerNodesQueryBuilder sort by [sulu:order] by default. This change is BC compatible as it does not matter if this column does not exist.
I can change it back, but technically its more correct. in_array returns a Boolean. The `!` checks for "falsy", i.e. `0`, false and empty string are all "false". But who even knows what goes on in PHP.