Added 3d model for the LM399

[PatrickBaus]

This is the PR for the 3d model of the LM399 voltage reference from here.

The real thing:

Two screenshots of the WRL file as redered by KiCAD:

I used KiCadStepUp with 'gold pins' for the legs and 'white body' for the plastic.

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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:

• [x] A screenshot of the model(s) aligned with KiCad footprint(s)
• [x] Source files are contributed on the apropriate location
  • Freecad source file can be found here.
• [x] Step model submitted in 1:1 scale
• [x] WRL model submitted in 1:2.54 scale
• [x] 3D model alignment checked against KiCad footprint
• [x] WRL model uses correct material properties
• [x] Geometry check performed on the model

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Be patient, we maintainers are volunteers with limited time and need to check your contribution against the datasheet. You can speed up the process by providing all the necessary information (see above).

[CLAassistant]

All committers have signed the CLA.

[diegoherranz]

Checks done on the STEP model:

• Height: 5.91mm measured. Datasheet defines 5.715 – 6.096, so 5.91 mm is right in the middle. - OK

• Diameter: 10.41 mm measured. Datasheet defines 10.160 – 10.668, so 10.41 mm is right in the middle. - OK

• Pin 0.44mm measured. Middle of 0.406 – 0.483 - OK

• Pitch 2.54mm - OK

• Checked that the alignment with the footprint works OK.

Looks OK. Thanks for the submission. Merging.