docs: restructure documentation pages

This removes the API section from index page and moves CLI and Python
docs into separate pages (creating separate sections in menu bar).

Also removes genindex, modindex, and search links - they were either
not functional or not useful.

docs/source/command_line_reference.rst

@@ -0,0 +1,10 @@
+Command line reference
+======================
+
+.. toctree::
+   :maxdepth: 1
+
+   generated/man/datalad-export-redcap-form
+   generated/man/datalad-export-redcap-project-xml
+   generated/man/datalad-export-redcap-report
+   generated/man/datalad-redcap-query.rst

docs/source/index.rst

@@ -17,57 +17,15 @@ GitHub::
   # install from GitHub main branch
   $ python -m pip install git+https://github.com/datalad/datalad-redcap.git@main
 
-
-API
-===
-
-High-level API commands
------------------------
-
-.. currentmodule:: datalad.api
-.. autosummary::
-   :toctree: generated
-
-   export_redcap_form
-   export_redcap_project_xml
-   export_redcap_report
-   redcap_query
-
-
-Command line reference
-----------------------
-
-.. toctree::
-   :maxdepth: 1
-
-   generated/man/datalad-export-redcap-form
-   generated/man/datalad-export-redcap-project-xml
-   generated/man/datalad-export-redcap-report
-   generated/man/datalad-redcap-query.rst
-
-
-User guide
-==========
+Index
+=====
 
 .. toctree::
    :maxdepth: 1
 
+   command_line_reference
+   python_module_reference
    user_guide
-
-Design
-======
-
-.. toctree::
-   :maxdepth: 1
-
    design_docs
 
-
-Indices and tables
-==================
-
-* :ref:`genindex`
-* :ref:`modindex`
-* :ref:`search`
-
 .. |---| unicode:: U+02014 .. em dash

docs/source/python_module_reference.rst

@@ -0,0 +1,11 @@
+Python API reference
+====================
+
+.. currentmodule:: datalad.api
+.. autosummary::
+   :toctree: generated
+
+   export_redcap_form
+   export_redcap_project_xml
+   export_redcap_report
+   redcap_query