Add ability to add model for diode_tht_sod123

[Grazfather]

relates to #9

Tested with:

      diode:
        what: ceoloide/diode_tht_sod123
        where: true
        params:
          from: "{{colrow}}"
          to: "{{row_net}}"
          include_tht: false
          reversible: false
          side: B
          diode_3dmodel_filename: ${SCOTTOKEEBS_KICAD}/3dmodels/ScottoKeebs_Components.3dshapes/Diode_SOD-123.step

(I got lucky and didn't need to move it at all)

Tested offset/scale/rotation manually.