ChemSpace v2.0.0

While this release contains almost the same functionality as the one previously published at gregory-kyro/ChemSpaceAL, the configuration class has been rewritten completely, so because the old function calls will not work with the current version of the code we have to bump up the major number of the version.

A minor addition relative to v1.0.3 is the support of filtering generations based on ADMET or by restricting certain functional groups. See tutorial notebook for an example of use.