Add "resourcesLoaded" plugin for Renderer

Provide the ability to modify resources before use.

lib/core/renderer.js

@@ -108,6 +108,9 @@ export default class Renderer extends Tapable {
       this.resources.loadingHTML = ''
     }
 
+    // Call resourcesLoaded plugin
+    await this.applyPluginsAsync('resourcesLoaded', this.resources)
+
     if (updated.length > 0) {
       // debug('Updated', updated.join(', '), isServer)
       this.createRenderer()