Add support for matrix operations

[lognorman20]

What is the problem you want to solve and can not with the current version?

I would like to do matrix operations using FheInts, but I am unable to use existing libraries such as tensor-rs or ndarray.

Describe the solution you'd like

An extension of this library that supports matrix operations on encrypted values

Describe alternatives you've considered

Writing my own implementations of matrix operations and representations

Additional context

Helpful for machine learning, computer graphics, phyics/engineering, etc...

[IceTDrinker]

Thanks for following up here

[IceTDrinker]

we now have some NdArrays with element wise ops