Fixing the error 'optional_dependencies'->'optional-dependencies', also...

I made a mistake in !18 (merged), so the optional dependencies didn't work.

Fixing the error 'optional_dependencies'->'optional-dependencies', also extending dependencies a bit

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UPD: How to test this:

1. make a new virtual environment

python -m venv venv_test && source venv_test/bin/activate

2. install the ntsim (assuming you're inside the repository directory):

pip install .

this shouldn't try installing and compiling nudisxs

3. install the ntsim with nupropagator:

pip install '.[nupropagator]'

this should additionally try to install nudisxs

4. install the gui libraries

pip install '.[gui]'

this should install also "pyqtgraph","PyOpenGL", "PyQt5","matplotlib" 5) delete the virtual env:

rm -rf venv_test