Small updates to documentation and adding .__version__ parameter

[xehu]

This pull requests makes some small cosmetic changes to the package:

1. It updates some of the headings in the "Worked Example" tab of the documentation;
2. It adds a .version parameter to the package upon installation, per PEP8 guidelines (Expose team_comm_tools.__version__ #318).
3. It reorders requirements.txt to restore alphabetical order.

[sundy1994]

Just to record what we've discussed: having both pyproject.toml and setup.py creates an additional point of maintenance and may cause conflicts in the future. We'd better stick with pyproject.toml as our sole configuration file. Instead, We can directly read the version number from pyproject.toml in init.py:

## __init__.py
from importlib.metadata import version as get_version

__version__ = get_version("team_comm_tools")

## test
>>> import team_comm_tools
>>> print(team_comm_tools.__version__)
>>> '0.1.5'

I'll make this change soon!