Create software architecture section to add swh-stories diagram

docs/sysadm/index.rst

@@ -10,6 +10,7 @@ Infrastructure
    puppet/index
    network-architecture/index
    server-architecture/index
+   software-architecture/index
    data-silos/index
    deployment/index
    user-management/index

docs/sysadm/software-architecture/index.rst

+.. _infrastucture_software_architecture:
+
+Software Architecture
+=====================
+.. toctree::
+   :titlesonly:
+
+   software-stories

docs/sysadm/software-architecture/software-stories.rst

+.. _software_stories:
+
+Software stories
+================
+
+Links
+-----
+
+* `software-stories.staging.swh.network <https://software-stories.staging.swh.network/>`_
+* `stories.softwareheritage.org <https://stories.softwareheritage.org/>`_
+
+Current diagram
+---------------
+
+.. figure:: ../images/infrastructure/software/swh-stories.png
+   :alt: Software Stories Application.