Removed old web ui plugin

Plugins/WebUI/Components/Layout/MainLayout.razor

@@ -1,23 +0,0 @@
-@inherits LayoutComponentBase
-
-<div class="page">
-    <div class="sidebar">
-        <NavMenu/>
-    </div>
-
-    <main>
-        <div class="top-row px-4">
-            <a href="https://learn.microsoft.com/aspnet/core/" target="_blank">About</a>
-        </div>
-
-        <article class="content px-4">
-            @Body
-        </article>
-    </main>
-</div>
-
-<div id="blazor-error-ui">
-    An unhandled error has occurred.
-    <a href="" class="reload">Reload</a>
-    <a class="dismiss">🗙</a>
-</div>