Consider adding an introduction for Tensors

[syedshazli]

In the current README, we dive into how Tensors are layed out in memory as well as tensor kernel development, but the reader is never introduced to what tensors are in the first place.

We can add a small section or 2 sentences before this that explain what a tensor is, and what tensor kernels are, before getting into memory layout

I can take this on, but just wanted input first.