add graph modules to support unstructured data

[pzhanggit]

This PR is to extend support for unstructured data, which is often seen in simulations.

• add an airfoil dataset example from deepmind, showing how to convert unstructured data into PyG graph Data objects
• Extended multidataset object to support PyG Data objects
• Extend SViT, ViT, and TurbT (with only one level for now) to support graph input data
• Add config examples for testing

[aprokop]

Partial review, still need to go through models and graph_datasets.py

Few questions:

• How did you choose what configs to include? For example, the difference between Demo_graph_vit.yaml and Demo_graph_svit.yaml is the usual differnce between ViT and SViT.
• Is there something special in submit_batch_graph.sh that is not covered by other examples we have?

[pzhanggit]

Partial review, still need to go through models and graph_datasets.py

Few questions:

• How did you choose what configs to include? For example, the difference between Demo_graph_vit.yaml and Demo_graph_svit.yaml is the usual differnce between ViT and SViT.
• Is there something special in submit_batch_graph.sh that is not covered by other examples we have?

Re configs, this PR provides graph supports for all different models that are possible and includes the corresponding configs.

Not sure what's the question about on submit_batch_graph.sh.

[TsChala]

I tried a bunch of test (MW_vit, flow3D, SOLPS with the leadtime fix, graph) and all of them worked. fine The SR test didn't work, the forward of turbt is not updated with opts.

[pzhanggit]

I tried a bunch of test (MW_vit, flow3D, SOLPS with the leadtime fix, graph) and all of them worked. fine The SR test didn't work, the forward of turbt is not updated with opts.

Thanks! I've addressed your comments. @TsChala let me know if you have more comments.

[TsChala]

After the fixes, it looks good to me!