Dummy class for testing purposes

[FNTwin]

For testing it would be useful to create a Dummy class that create the required memmap files with 2/3 molecules.

from openqdc.datasets import Dummy
ds = Dummy() 

Dummy would write on the cache a small precomputed dataset of 2-3 molecules as the required memmap files and thus would avoid the issue of downloading a dataset for initializing the tests.