Revert "remove support for KnpBundle 1.x"

This reverts commit e7dc89ce8b4da8ababa8a8648cfe9232f3666522.
fix compatibility support with knpmenu 1.X and 2.X
replace tabs with spaces
Update recipe_file_uploads.rst

We have to change field name from 'file' into 'filename' while we need field 'file' to be not mapped. Field 'file' is only temporary to store UploadedFile instance.
Merge pull request #2318 from trujamii/patch-1

Update recipe_file_uploads.rst
Merge remote-tracking branch 'sonata-project/master'