SolarPanel <Pivots> generated from empties

[THDigi]

SE v204 added <Pivots> to solar panel definitions which allows modders to define where the rays come from and how many of them.

This suggestion is to generate that tag from model empties to be easier to visualize (especially as the new F11 solar panels draw isn't that useful).

Example of the tag, more in CubeBlocks_DecorativePack3.sbc.

<Pivots>
  <Vector3>
    <X>-0.5</X>
    <Y>0</Y>
    <Z>0</Z>
  </Vector3>
  <Vector3>
    <X>-0.5</X>
    <Y>0</Y>
    <Z>-0.5</Z>
  </Vector3>
  ... etc
</Pivots>

Units are in cell sizes (gets multiplied by grid size in meters on load) and floating point as you can see so it's not limited to the center of a cell.

[THDigi]

Z is flipped btw, positive values offset towards forward not backward 😒