Upgrade to FontAwesome 5 (take two) (#6673)

* Add missing icons to set

* Revert FA5 revert

 This reverts commit 42572ff

* use new SVG syntax in locales

* Noscript page changes (remove login button, center "powered by" footer text)

* Cast wider net for SVG icons in settings

- include any _icon setting for SVG registry (offers better support for plugin settings)

- let themes store multiple pipe-delimited icons in a setting

- also replaces broken onebox image icon with SVG reference in cooked post processor

* interpolate icons in locales

* Fix composer whisper icon alignment

* Add support for stacked icons

* SECURITY: enforce hostname to match discourse hostname

This ensures that the hostname rails uses for various helpers always matches
the Discourse hostname

* load SVG sprite with pre-initializers

* FIX: enable caching on SVG sprites

* PERF: use JSONP for SVG sprites so they are served from CDN

This avoids needing to deal with CORS for loading of the SVG

Note, added the svg- prefix to the filename so we can quickly tell in
dev tools what the file is

* Add missing SVG sprite JSONP script to CSP

* Upgrade to FA 5.5.0

* Add support for all FA4.7 icons

- adds complete frontend and backend for renamed FA4.7 icons

- improves performance of SvgSprite.bundle and SvgSprite.all_icons

* Fix group avatar flair preview

- adds an endpoint at /svg-sprites/search/:keyword

- adds frontend ajax call that pulls icon in avatar flair preview even when it is not in subset

* Remove FA 4.7 font files

plugins/poll/assets/javascripts/discourse/templates/modal/poll-ui-builder.hbs

@@ -82,5 +82,5 @@
 {{/d-modal-body}}
 
 <div class="modal-footer">
-  {{d-button action="insertPoll" icon="bar-chart-o" class='btn-primary' label='poll.ui_builder.insert' disabled=disableInsert}}
+  {{d-button action="insertPoll" icon="chart-bar" class='btn-primary' label='poll.ui_builder.insert' disabled=disableInsert}}
 </div>

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"
     };

plugins/poll/assets/javascripts/widgets/discourse-poll.js.es6

@@ -42,9 +42,9 @@ createWidget("discourse-poll-option", {
     const chosen = vote.includes(option.id);
 
     if (attrs.isMultiple) {
-      contents.push(iconNode(chosen ? "check-square-o" : "square-o"));
+      contents.push(iconNode(chosen ? "far-check-square" : "far-square"));
     } else {
-      contents.push(iconNode(chosen ? "dot-circle-o" : "circle-o"));
+      contents.push(iconNode(chosen ? "far-dot-circle" : "far-circle"));
     }
 
     contents.push(" ");