Temporarily added MudBlazor.Markdown to the solution

This is necessary due to issue https://github.com/MyNihongo/MudBlazor.Markdown/issues/247

I created a PR as well: https://github.com/MyNihongo/MudBlazor.Markdown/pull/246

MudBlazor.Markdown/Services/Interfaces/IMudMarkdownClipboardService.cs

@@ -0,0 +1,6 @@
+namespace MudBlazor;
+
+public interface IMudMarkdownClipboardService
+{
+	ValueTask CopyToClipboardAsync(string text);
+}

MudBlazor.Markdown/Services/Interfaces/IMudMarkdownThemeService.cs

@@ -0,0 +1,8 @@
+namespace MudBlazor;
+
+public interface IMudMarkdownThemeService
+{
+	event EventHandler<CodeBlockTheme> CodeBlockThemeChanged;
+
+	void SetCodeBlockTheme(CodeBlockTheme theme);
+}