first attempt at numpy.distutils conversion to meson

[dxiao]

This should begin to fix #8

• Convert setup.py -> pyproject.toml
• Remove VERSION file in favor of having information in pyproject.toml directly
• Add meson.build files for okada_wrapper and DC3D modules Conversion was done according to information at https://numpy.org/doc/stable/f2py/buildtools/meson.html

Note:

• This commit gets pip install . to work, import okada_wrapper to work, but not test_okada.py yet. Help would be appreciated. Current error is:

  $ python test_okada.py
  /home/dxiao/code/okada_wrapper/test_okada.py:45: SyntaxWarning: invalid escape sequence '\l'
  cbar.set_label('$\log(u_{\\textrm{x}})$')
  Traceback (most recent call last):
  File "/home/dxiao/code/okada_wrapper/test_okada.py", line 103, in <module>
  test_dc3d()
  File "/home/dxiao/code/okada_wrapper/test_okada.py", line 56, in test_dc3d
  success, u, grad_u = dc3dwrapper(alpha,
                       ^^^^^^^^^^^^^^^^^^
  File "/home/dxiao/code/okada_wrapper/okada_wrapper/okada_wrapper.py", line 22, in dc3dwrapper
  dc3d(alpha, xo[0], xo[1], xo[2], depth, dip, strike_width[0],
  TypeError: DC3D.dc3d() missing required argument 'ux' (pos 14)