CleanUp Rauk module

[RichRick1]

Description

There are few improvement that can be done to the Rauk’s dictionary module

• Move [this code block](https://github.com/theochem/ModelHamiltonian/blob/41985d33b0f5c9c5c1a9cfcf72eb3989e164a519/moha/api.py#L46C8-L54C44) into stand-alone function inside [utils.py](http://rauk.utils.py/) file in rauk module. Call it get_n_sites(connectivity). In this file should also go get_atom_types function from the utils.py file inside the moha module. This function can be used to implement functionality below.
• Remove dependency on atom_types and n_sites parameters. This can be done by iterating over the connectivity instead of atom_types in [this block](

  ModelHamiltonian/moha/rauk/rauk.py

  Lines 120 to 123 in 41985d3

  	# Create atom dictionary using predefined values without overlap
  	# parameters
  	for atom in atom_types:
  	atom_dictionary[atom] = alpha_c + hx_dictionary[atom] * abs(beta_c)

  ).
• Remove dependency on n_sites from build_one_body parameters. This can be done by computing parameter n_sites inside the function.

[giovanni-br]

I've cleaned the discussed points and I've changed the docstring a function that was clearly wrong.