feat: Add new Geometry Nodes groups for image relief and shadeless shader

- Implemented the "O Image Relief Plane" Geometry Nodes group to create a fixed-base image relief using depth images and various parameters.
- Created the "O Shadeless" shader node group to display color without scene lighting while preserving shadows and reflections.
- Introduced a preview feature for node groups, allowing for interactive visualization of node arrangements in an HTML format.
- Added a template HTML file for rendering node previews with customizable views and controls.

tests/test_material_view_adaptation.py

@@ -145,7 +145,7 @@ def test_new_material_uses_current_preference_and_preserves_existing(color_data,
     }
     with patch.object(preferences, "addon_preferences", return_value=settings):
         if entry == "clipboard":
-            first = clipboard._create_image_material(source, shadeless, scene=scene)
+            first = clipboard.create_image_material(source, source, shadeless=shadeless, scene=scene)
         else:
             if entry == "plane":
                 color = create_color_image(owner)
@@ -153,16 +153,16 @@ def test_new_material_uses_current_preference_and_preserves_existing(color_data,
                 color = create_cropped_color_image(owner, (0, 0, 2, 2), images.image_rgba(source))
             else:
                 color = source
-            first = material.create_image_material(owner, color, 0, shadeless=shadeless, scene=scene, **data_textures)
+            first = material.create_image_material(owner.data, color, 0, shadeless=shadeless, scene=scene, **data_textures)
         original_color = color_texture(first)
         assert original_color.colorspace_settings.name == "AgX Base sRGB"
         assert original_color.alpha_mode == "STRAIGHT"
         settings.adapt_material_to_view_transform = False
         assert original_color.alpha_mode == "STRAIGHT"
         if entry == "clipboard":
-            second = clipboard._create_image_material(original_color, shadeless, scene=scene)
+            second = clipboard.create_image_material(original_color, original_color, shadeless=shadeless, scene=scene)
         else:
-            second = material.create_image_material(owner, original_color, 0, shadeless=shadeless, scene=scene)
+            second = material.create_image_material(owner.data, original_color, 0, shadeless=shadeless, scene=scene)
         new_color = color_texture(second)
         assert new_color != original_color
         assert new_color.colorspace_settings.name == "sRGB"