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

plugins/poll/assets/javascripts/initializers/add-poll-ui-builder.js.es6

@@ -32,7 +32,7 @@ function initializePollUIBuilder(api) {
   api.addToolbarPopupMenuOptionsCallback(function() {
     return {
       action: "showPollBuilder",
-      icon: "bar-chart-o",
+      icon: "chart-bar",
       label: "poll.ui_builder.title",
       condition: "canBuildPoll"
     };