refactor: Move Sprocket JS files to Webpack (Part 1) (#3025)

* refactor: Move Sprocket JS files to Webpack (Part 1)

JavaScript for RfCs, Flashes and the color mode can be moved without
modifications.

Relates to #3021

* kebab case

* Move flash messages CSS to app.

* Use require avoiding hoisted imports

Author: arkirchner

app/assets/javascripts/application.js

@@ -13,10 +13,6 @@
 //= require rails-timeago
 //= require locales/jquery.timeago.de.js
 //
-// lib/assets
-//= require flash
-//= require color_mode_picker
-//
 // app/assets
 // --> Include some assets first, as they are used by other assets.
 // --> Hence, the order specified here is important.

app/assets/stylesheets/application.css

@@ -10,10 +10,6 @@
  * files in this directory. Styles in this file should be added after the last require_* statement.
  * It is generally better to create a new file per style scope.
  *
- * lib/assets
- *= require flash
- *
- * app/assets
  *= require_tree .
  *= require_self
  */

lib/assets/stylesheets/flash.css.scss renamed to app/assets/stylesheets/flash.css.scss

@@ -88,3 +88,7 @@ window.ace = ace; // Publish ace in global namespace
 // Turbo
 import '@hotwired/turbo-rails';
 import './turbo-migration';
+
+// Import of Rails sprocket assets with minimal changes. After the initial migration these files should
+// be moved to an appropriate place after some adjustments to fit modern Rails JS.
+require('sprocket-asset-import');

app/javascript/application.js

@@ -0,0 +1,4 @@
+require('./flash');
+require('./color-mode-picker');
+
+require('./request-for-comments');