[FEAT] Complete planet.csv file

[aaronjridley]

Is your feature request related to a problem? Please describe.
For every planet, there needs to be a relationship between the longitude and the local time. These are related through the length of a day, the time, and a reference longitude. The reference longitude is the longitude which was at midnight local time on January 1, 2000 at 00 UT. Given these quantities, the local time can be calculated for any time.

At this point, there is column in the planet file for the reference longitude, but it is wrong for all of the planets except for Earth. This needs to be fixed and tests should be made for each planet.

Describe the solution you'd like

1. research the reference longitudes for each planet and add into the planets file.
2. create tests for a few planets to verify that they all work ok.

Describe alternatives you've considered
I am not entirely certain where to find this information. So, we need to do a bunch of research on this.

[aaronjridley]

From my understanding, the longitude of several gas giant planets doesn't really matter. Tests should still be created for each planet, though.