DEV: Merge topic list card component (#17)

This PR merges the topic-list-item card component into the nextgen theme.

Also does the following cleanup:

* Use template-only ember components
* Use `fire` instead of deprecated `fa-fire` icon
* Lower version requirement for node to 18 to match core
* Add english locale strings for topic status column
* Remove dummy theme settings

---------

Co-authored-by: Martin Brennan <martin@discourse.org>

locales/en.yml

@@ -1,5 +1,12 @@
 en:
   theme_metadata:
-    description: ""
-    settings:
-      example_setting: A description of a setting.
+    description: "A simple, beautiful theme for the future of Discourse that improves the out of the box experience for sites."
+  topic_bookmarked: "Bookmarked"
+  topic_closed_archived: "Closed and archived"
+  topic_closed: "Closed"
+  topic_archived: "Archived"
+  topic_warning: "Warning"
+  topic_personal_message: "Personal message"
+  topic_pinned: "Pinned"
+  topic_unpinned: "Unpinned"
+  topic_hot: "Hot"