Add Tensor structures and operations

Currently, there is no support for some of the Tensor operations, also it would be helpful to have a structures/aliases named `Tensor*` of any dimensionality.

There are exist two small Rust libraries but they are incomplete or abandoned:
- https://github.com/alphal00p/spenso
- https://github.com/wildfunctions/tensor

And a small implementation inside Candle:
- https://github.com/huggingface/candle/blob/main/candle-core/src/tensor.rs

I believe, nalgebra *is* the place to implement it, since most of the code is already here, just some minor modifications are needed

See also:
- https://github.com/pytearcat/pytearcat
- https://arxiv.org/pdf/2106.15016
- https://hal.science/hal-03298805v1/file/tensors.pdf