Closes #3030 numpy alignment directory structure

[ajpotts]

Closes #3030 numpy alignment directory structure

Creates a directory for numpy code, and sets up the init.py file. Also, imports numpy dtypes so that the following can be called from arkouda:

import arkouda.numpy as aknp
In [2]: aknp.int64
Out[2]: numpy.int64

Also, renamed the "akscipy" module to "scipy" for more consistent naming convention.

[stress-tess]

Looks good to me!