Adding Custom Orbit Objects/Orbit Paths

[joaq-ram]

The ability to visualize orbits of custom celestial objects or spacecraft via orbit paths/models. This capability exists in pyWWT for visualizing planetary orbits in the solar system view but not for individual spacecraft/ custom objects.

Implementation:

• Specify orbital object position and time via SPICE kernels
• Visualize the orbit path with a customizable tail (change thickness, color, longevity)