Create card components and add them to dashboard

Refactor the Releases, Modules and Projects cards into reusable
templates. Now they are used in the non-logged-in landing homepage
and in the logged-in dashboard.

templates/custom/header.tmpl

@@ -0,0 +1,20 @@
+<style>
+    .page-content.home ul,
+    .page-content.dashboard ul{
+        padding-inline-start: 15px;
+    }
+
+    ul.two-col {
+        columns: 2;
+    }
+
+    .page-content.home .ui.cards>.card, .ui.card,
+    .page-content.dashboard .ui.cards>.card, .ui.card {
+        width: 100%;
+    }
+
+    .page-content.home .hero p {
+        width: 70%;
+        font-size: 1.2rem;
+    }
+</style>