Modernize installation and workflows

[Jack-42]

Although the use of setup.py is still valid, it's recommended to include a pyproject.toml file in Python packages, see:
https://packaging.python.org/en/latest/guides/modernize-setup-py-project/

Additionally, we should add a GitHub workflow that automatically updates the PyPI version upon release:
https://jackwhitworth.com/blog/automatically-update-pypi-on-github-release/

[Jack-42]

We also should make sure that the pip install option downloads all dependencies. See issue below:

(rdktools_test) jack@computer:~$ pip install rdktools
Defaulting to user installation because normal site-packages is not writeable
Collecting rdktools
  Downloading rdktools-0.9.8-py3-none-any.whl (107 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 107.1/107.1 KB 2.6 MB/s eta 0:00:00
Installing collected packages: rdktools
Successfully installed rdktools-0.9.8
(rdktools_test) jack@computer:~$ python3 -m rdktools.formats.App -h
Traceback (most recent call last):
  File "/usr/lib/python3.10/runpy.py", line 187, in _run_module_as_main
    mod_name, mod_spec, code = _get_module_details(mod_name, _Error)
  File "/usr/lib/python3.10/runpy.py", line 110, in _get_module_details
    __import__(pkg_name)
  File "/home/jack/.local/lib/python3.10/site-packages/rdktools/formats/__init__.py", line 1, in <module>
    from .Utils import *
  File "/home/jack/.local/lib/python3.10/site-packages/rdktools/formats/Utils.py", line 5, in <module>
    import rdkit.Chem
ModuleNotFoundError: No module named 'rdkit'