Convert muse into a command

[dalonsoa]

After #103

Convert muse into a command, so you can use muse settings.toml for running MUSE instead of python -m muse settings.toml.

To do this, an appropriate entry point in pyproject.toml must be created pointing (probably) to muse/__main__.py, but this will need to be confirmed.

While it seems like a minor change, the above will enable the use of pipx, keeping MUSE within its own virtual environment (without the user needing to create it manually), simplifying future updates and allowing it to be used anywhere in the OS.

[jamesturner246]

I'll take this.

[jamesturner246]

Done. I can't seem to link the PR to this task, but it's #118 .