Implement `aesara.tensor.matmul`

[rlouf]

As in https://numpy.org/doc/stable/reference/generated/numpy.matmul.html

[zoj613]

@brandonwillard where would the implementation be put? (basic.py vs math.py vs nlinalg.py). Also which of the input parameters should be ignored for the aesara implementation?

[brandonwillard]

@brandonwillard where would the implementation be put? (basic.py vs math.py vs nlinalg.py).

nlinalg seems like the right place.

Also which of the input parameters should be ignored for the aesara implementation?

out, order, subok, and casting aren't relevant to Aesara right now.

[brandonwillard]

We need to finish https://github.com/aesara-devs/aesara/pull/757 in order to complete our matmul implementation. See the comments in https://github.com/aesara-devs/aesara/pull/744.