implement `aesara.tensor.multiply`

[rlouf]

For API compatibility. numpy.multiply is an alias for *, the element-wise multiplication. https://numpy.org/doc/stable/reference/generated/numpy.multiply.html?highlight=multiply#numpy.multiply

[unnumsykar]

I am new, how can I start on this issue ??

[ricardoV94]

@unnumsykar this PR could give an idea: https://github.com/aesara-devs/aesara/pull/490

[brandonwillard]

Also, this would probably just be an alias for aesara.tensor.math.mul.

[rlouf]

There shouldn't be anything to implement here, the idea is to add an alias to get Aesara's API closer to numpy's. Or better, replace the use of mul by multiply, use mul as an alias and add a deprecation warning.