Include shape in array types

[mdbenito]

Using nptyping and beartype we can pin down the dimensions that we accept. For instance, the constructor of ValuationResult can only accept 1D arrays but we don't enforce that.

Alternatively, jaxtyping supports jax, torch and numpy in one go. But python 3.9 is required so we'd have to wait until EOL for 3.8 at the very least.

Are there any other libraries?

[mdbenito]

@janosg @schroedk this could be a valid reason to expedite deprecation of 3.8