Extracted some pages to their own assembly and finished the artifact display page code

OpenArchival.Blazor.FileViewer/FileViewers/UnsupportedFileViewer.razor

@@ -0,0 +1,16 @@
+@namespace OpenArchival.Blazor.FileViewer
+
+@using MudBlazor
+@using OpenArchival.DataAccess
+
+@implements IFileViewer;
+
+<MudText Typo="Typo.h2">File unsupported</MudText>
+
+@code {
+    [Parameter]
+    public required FilePathListing File { get; set; } 
+
+    [Parameter]
+    public EventCallback<int> OnHeightMeasured { get; set; }
+}