[DOCS] Re-structured documentation hierarchy

docs/conf.py

@@ -35,11 +35,13 @@ autosectionlabel_prefix_document = True
 
 # Sphinx gallery
 extensions += ['sphinx_gallery.gen_gallery']
+from sphinx_gallery.sorting import FileNameSortKey
 sphinx_gallery_conf = {
     'examples_dirs': '../python/tutorials/',
-    'gallery_dirs': 'tutorials',
+    'gallery_dirs': 'getting-started/tutorials',
     'filename_pattern': '',
     'ignore_pattern': r'__init__\.py',
+    'within_subsection_order': FileNameSortKey,
 }
 
 # Add any paths that contain templates here, relative to this directory.