UI ember engines (#6718)

Adds replication engine and core in-repo addon

ui/lib/core/addon/components/empty-state.js

@@ -0,0 +1,24 @@
+import Component from '@ember/component';
+import layout from '../templates/components/empty-state';
+
+/**
+ * @module EmptyState
+ * `EmptyState` components are used to render a helpful message and any necessary content when a user
+ * encounters a state that would usually be blank.
+ *
+ * @example
+ * ```js
+ * <EmptyState @title="You don't have an secrets yet" @message="An explanation of why you don't have any secrets but also you maybe want to create one." />
+ * ```
+ *
+ * @param title=null{String} - A short label for the empty state
+ * @param message=null{String} - A description of why a user might be seeing the empty state and possibly instructions for actions they may take.
+ *
+ */
+
+export default Component.extend({
+  layout,
+  tagName: '',
+  title: null,
+  message: null,
+});