add generation of api doc

.gitlab-ci.yml

@@ -8,6 +8,7 @@ docs:
     - tags
   script:
     - cd docs
+    - nix-shell -p python3Packages.sphinx python3Packages.sphinx_rtd_theme python3Packages.numpydoc python3Packages.pnam --run 'sphinx-apidoc -M -f -o Manual/src ../proxtoolbox ../proxtoolbox/Algorithms_old ../proxtoolbox/Problems_old ../proxtoolbox/ProxOperators_old ../proxtoolbox/algorithms/samsara/debug'
     - nix-shell -p python3Packages.sphinx python3Packages.sphinx_rtd_theme python3Packages.numpydoc python3Packages.pnam --run 'env -u SOURCE_DATE_EPOCH make html'
   artifacts:
     paths: