Reformating the SORA modules

In this PR, I reformated the SORA modules to improve the management of the code. They were mainly divided into 4 files:

CORE, where we have the main Class of the module.
UTILS, where we have functions used by the main module that the users can call to use themselves.
META, where we have functions used by the main module but it's not useful for the user to call.
VALUES, where we maintain some dictionaries, strings or list to not populate the other files.
Other files, as seem fit.

Other updates were:

Addition of the Gaia-EDR3 in the prediction function.
Fixed of bug that happened when an Ephem object without spkid was added to the Body object.
Fixed bug when plotting the heights in the map in a rotated projection. #54
Added function that adds two ChiSquare objects and returns a combined one chi3 = chi1 + chi2
Created a hardcoded satellite database to complement missing data of SBDB. It must be replaced in the future.
Update the argument "log" to "verbose".
Update the imports for faster initialization.

riogroup / SORA