kgcnn v3.0.0

Major refactoring of kgcnn layers and models.
We try to provide the most important layers for graph convolution as kgcnn.layers with ragged tensor representation.
As for literature models only input and output is matched with kgcnn .

• Move kgcnn.layers.conv to kgcnn.literature .
• Refactored all graph methods in graph.methods .
• Moved kgcnn.mol.* and kgcnn.moldyn.* into kgcnn.molecule
• Moved hyper into trainig
• Updated crystal .