Adding support for simplifying powers of tensorproducts
Adding support for simplifying powers of tensorproducts

This commit adds support for `tensor_product_simp()` to also handle `Pow`
expressions with tensorproducts.

There is a new function `tensor_product_simp_Pow()` that only evaluates powers
whose base is a tensorproduct, and `tensor_product_simp_Mul()` has been
changed to call `tensor_product_simp_Pow()` when appropraite.

This solves issue #13779, resolves one of the "TODO" items present in a
comment in `tensorproduct.py` (comment has been changed) and is an alternative
solution to the PR #13784.

kaushik94/sympy,kaushik94/sympy,kaushik94/sympy