Add site layout with header navigation and footer

Elternbeirat.Web/Components/Layout/MainLayout.razor

@@ -1,3 +1,33 @@
-@inherits LayoutComponentBase
+@inherits LayoutComponentBase
 
-@Body
+<div class="page">
+    <header class="site-header">
+        <div class="header-inner">
+            <a class="brand" href="/">Elternbeirat IGMH</a>
+            <nav class="main-nav">
+                <NavLink href="/" Match="NavLinkMatch.All">Start</NavLink>
+                <NavLink href="/vorstandsteam">Vorstandsteam</NavLink>
+                <NavLink href="/foerderverein">Förderverein</NavLink>
+                <NavLink href="/beitraege">Beiträge</NavLink>
+                <NavLink href="/faq">FAQ</NavLink>
+                <NavLink href="/downloads">Downloads</NavLink>
+                <NavLink href="/kontakt">Kontakt</NavLink>
+            </nav>
+        </div>
+    </header>
+
+    <main class="content">
+        @Body
+    </main>
+
+    <footer class="site-footer">
+        <div class="footer-inner">
+            <span>Elternbeirat der IGMH</span>
+            <nav class="footer-nav">
+                <a href="/kontakt">Kontakt</a>
+                <a href="/impressum">Impressum</a>
+                <a href="/datenschutz">Datenschutz</a>
+            </nav>
+        </div>
+    </footer>
+</div>