switch_choc_v1_v2: Add param to add 3D model

[Grazfather]

This PR adds an param to switch_choc_v1_v2, allowing the user to specify a path to a model file for 3D rendering.

I tested using https://github.com/joe-scotto/scottokeebs/blob/main/Extras/ScottoKicad/3dmodels/ScottoKeebs_Choc.3dshapes/Choc_V1.step, which I have on my local system, added as a library.

My config.yaml uses it like so:

    footprints:
      key_switches:
        what: ceoloide/switch_choc_v1_v2
        where: true
        params:
          hotswap: true
          reversible: false
          side: B
          from: "{{column_net}}"
          to: "{{colrow}}"
          choc_v2_support: false
          show_keycaps: true
          keycaps_x: keycw
          keycaps_y: keych
          switch_model_filename: ${SCOTTOKEEBS_KICAD}/3dmodels/ScottoKeebs_Choc.3dshapes/Choc_V1.step

I had to rotate the model to get it to line up, which suggest that that might be an issue for other models. We might want to add params that allow manual shifting or rotating.