Added PowerPoint templates to the Slide Assistant (#1055)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Tools/PowerPoint/LayoutVariant.cs

@@ -0,0 +1,8 @@
+namespace AIStudio.Tools.PowerPoint;
+
+/// <summary>
+/// One variant of a layout family, e.g., the green version of a content layout.
+/// </summary>
+/// <param name="Label">The part of the layout name which tells the variants apart, e.g., "B"; null for a family of a single layout.</param>
+/// <param name="Layout">The layout.</param>
+internal sealed record LayoutVariant(string? Label, TemplateLayout Layout);