Europa Clipper scale model modified

Modifications:
* Added solar cells part (print 10)
* Split MinusY into separate parts: MinusY (body), HGA front, HGA back
* Simplified PluxX and MinusX geometry (eliminated extra connections between solar panels for cleaner first layer)

Print 10 "solar_cells" panels and glue to PlusX and MinusX solar array backing structure using modeling glue or CA. To make the extrusion tracks appear like horizontal arrays of solar cells (rather than default diagonal tracks), in Cura, set "top/bottom line direction" to [90, 0].