Scripted version of generic qfn 40, 42, 44 and 48

This adds scripted versions for the qfn 4x footprints (some qfn 48 where already scripted these are not touched)

Script PR is https://github.com/pointhi/kicad-footprint-generator/pull/149 (file qfn-4x.yaml, replaces qfn-48.yaml)

Footprint QFN-44-1EP_9x9mm_P0.65mm_EP7.5x7.5mm is not replaced. (Missing dimensions in the datasheet and the issue regarding naming convention. See https://github.com/KiCad/kicad-footprints/issues/769)

Footprint QFN-44-1EP_7x7mm_P0.5mm_EP5.4x5.4mm might not be needed anymore. (See symbol PR: https://github.com/KiCad/kicad-symbols/pull/781) Not part of this PR for this reason.