Consider removing old shape handling functions

[ricardoV94]

Now that random draws are done by Aesara, we might not need some/all of these anymore:

https://github.com/pymc-devs/pymc/blob/761f77dad29116650ef3ca043645042219654a5c/pymc/distributions/shape_utils.py#L38-L42

First step would be to check which ones are still used and where.

[Armavica]

As far as I can say,

• shapes_broadcasting is only used in broadcast_dist_samples_shape and get_broadcastable_dist_samples,
• broadcast_dist_samples_shape is only used in get_broadcastable_dist_samples,
• get_broadcastable_dist_samples is only used in broadcast_distribution_samples and broadcast_dist_samples_to,
• broadcast_distribution_samples is not used anywhere,
• broadcast_dist_samples_to is the only of these functions used somewhere else in the code, and only in MatrixNormalRV.

[ricardoV94]

So we should check if we can get something more immediate to replace broadcast_dist_samples_to in MatrixNormalRV? I haven't looked at what it is doing

[mattiadg]

Is this still an open issue? I am interested in working on it