add smt mounting hardware by wuerth

Script see: https://github.com/pointhi/kicad-footprint-generator/pull/351

yaml file generated from product page tables. (every part has its own datasheet, but the datasheets of every series have equivalent dimensioned drawings in them. The product pages are the best to use for checking the part numbers vs height.) https://katalog.we-online.com/en/em/browse/assembly/smd_spacer

I am not really sure about the naming convention (for both footprints and the library.) If anybody has a suggestion i am all for it.

3d model pull request: https://github.com/KiCad/kicad-packages3D/pull/557

example screenshots