listAvailablePlanetaryEphemerides: List Available Planetary Ephemerides Files
Description
This function lists all available JPL DE ephemerides files (with .bsp extension).
More JPL DE ephemerides files can be downloaded from the JPL Horizons website (https://ssd.jpl.nasa.gov/?horizons),
and registered with the registerPlanetaryEphemerides.
Usage
listAvailablePlanetaryEphemerides()
Value
Returns a vector of filenames of the available JPL DE ephemerides files.