Add JST XAD, 8-20 Pin, Vertical

[bveenema]

Add 3D models for XAD seriers JST connectors. See pull request in footprints: https://github.com/KiCad/kicad-footprints/pull/2310

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Thanks for creating a pull request to contribute to the KiCad libraries! Remember you must be the legal owner of the 3D model! Models downloaded from a manufacturers website cannot be accepted.

To speed up integration of your PR, please check the following items as you complete them:

• [ ] A screenshot of the model(s) aligned with KiCad footprint(s)
• [ ] Source files are contributed on the apropriate location
  • Link to the package3d-source pull request or to the script pull request
• [ ] Step model submitted in 1:1 scale
• [ ] WRL model submitted in 1:2.54 scale
• [ ] 3D model alignment checked against KiCad footprint
• [ ] WRL model uses correct material properties
• [ ] Geometry check performed on the model

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