docs: add Sphinx documentation build and deploy workflow

- Add Gitea Actions workflow to build and deploy docs on push to main
- Generate Sphinx reference documentation for all apps and modules
- Deploy versioned and latest docs via rsync over SSH

docs/source/reference/apps/llm_manager/llm_manager.rst

@@ -0,0 +1,32 @@
+llm\_manager package
+====================
+
+.. automodule:: llm_manager
+   :members:
+   :show-inheritance:
+   :undoc-members:
+
+Subpackages
+-----------
+
+.. toctree::
+   :maxdepth: 4
+
+   llm_manager.api
+   llm_manager.management
+
+Submodules
+----------
+
+.. toctree::
+   :maxdepth: 4
+
+   llm_manager.admin
+   llm_manager.apps
+   llm_manager.encryption
+   llm_manager.forms
+   llm_manager.models
+   llm_manager.services
+   llm_manager.tasks
+   llm_manager.urls
+   llm_manager.views