GNNs for keras models

[PatReis]

Hello @fchollet ,
I just saw that keras is merging NLP and CV into a models repo.
If there is interest from the keras team to also include Graph Neural Networks, I am eager to contribute or become involved.
I reworked kgcnn for keras 3 and it works nicely, although I would have removed lots of the clutter but I tried to stay backward compatible.
Of course, I would do things differently and much cleaner when starting over!
In my opinion, it is important to be compatible with PyG and the disjoint graph representation for keras models as well, so that people can use their input pipelines.
Does keras have a different strategy? What do you think?