feat(announcement): Add End of Life announcement

site/layouts/partials/announcement.html

@@ -0,0 +1,17 @@
+<div class="d-block px-3 py-2 text-center text-bold bd-announcement">
+  Bootstrap 4 has reached end of life.
+  <a
+    href="https://getbootstrap.com/docs/5.3/migration/"
+    target="_blank"
+    rel="noopener"
+    >Upgrade to the latest</a
+  >
+  or consider
+  <a
+    href="https://www.herodevs.com/support/nes-bootstrap?utm_source=Bootstrap_site&utm_medium=Banner&utm_campaign=v4_eol"
+    target="_blank"
+    rel="noopener"
+    >Never-Ending-Support</a
+  >
+  for your project
+</div>