gnu: python-scipy: Update to 1.9.1.

gnu: python-scipy: Update to 1.9.1.

* gnu/packages/python-science.scm (python-scipy): Update to 1.9.1.
[source]: Switch to GIT-FETCH.
[outputs]: Remove.
[arguments]: Don't disable Pythran.  Don't configure OpenBLAS which is now
discovered by pkg-config.  Do a "manual" PEP 517 style build.  Make
install-doc phase conditional on the presence of Sphinx.  Simplify tests.
[propagated-inputs]: Add PYTHON-PYTHRAN.
[native-inputs]: Remove PERL, WHICH, PYTHON-NUMPYDOC,
PYTHON-PYDATA-SPHINX-THEME, PYTHON-SPHINX, and PYTHON-SPHINX-PANELS.  Add
GCC, PKG-CONFIG, PYTHON-PYPA-BUILD and PYTHON-MESON.