New all-icons helper that's really only meant for development use

This returns an array of all icons. As the comment suggests, it's
because the SVGs file can't be imported in stories since it is generated
as part of the Ember project.

ui/app/helpers/all-icons.js

@@ -0,0 +1,18 @@
+import { helper } from '@ember/component/helper';
+
+// Generated at compile-time by ember-inline-svg
+import SVGs from '../svgs';
+
+/**
+ * Icons array
+ *
+ * Usage: {{#each (all-icons) as |icon|}}
+ *
+ * Returns the array of all icon strings available to {{x-icon}}. This is a bit of a hack
+ * since the above SVGs import isn't available in the Storybook context.
+ */
+export function allIcons() {
+  return Object.keys(SVGs);
+}
+
+export default helper(allIcons);