FEATURE: Update Font Awesome to v5.4.1 and SVGs (#6557)

* First take on subsetting svg icons

* FontAwesome 5 svg subset WIP

* Include icons from plugins/badges into svg sprite subset

* add svg icon support to themes

* Add spec for SvgSprite

* Misc. SVG icon fixes

* Use FA5 svgs in local-dates plugin

* CSS adjustments, fix SVG icons in group flair

* Use SVG icons in poll plugin

* Add SVG icons to /wizard

test/javascripts/components/d-icon-test.js.es6

@@ -9,7 +9,10 @@ componentTest("default", {
     const html = this.$()
       .html()
       .trim();
-    assert.equal(html, '<i class="fa fa-bars d-icon d-icon-bars"></i>');
+    assert.equal(
+      html,
+      '<svg class="fa d-icon d-icon-bars svg-icon svg-string" xmlns="http://www.w3.org/2000/svg"><use xlink:href="#bars"></use></svg>'
+    );
   }
 });
 
@@ -22,7 +25,7 @@ componentTest("with replacement", {
       .trim();
     assert.equal(
       html,
-      '<i class="fa fa-exclamation-circle d-icon d-icon-d-watching"></i>'
+      '<svg class="fa d-icon d-icon-d-watching svg-icon svg-string" xmlns="http://www.w3.org/2000/svg"><use xlink:href="#exclamation-circle"></use></svg>'
     );
   }
 });