JS: Upated npm deps, upgraded eslint, new eslint config

Upgraded eslint to 11, removed incompatible airbnb config as part of
process. ESlint config now in its own file.

resources/js/components/page-editor.js

@@ -138,7 +138,7 @@ export class PageEditor extends Component {
 
             didSave = true;
             this.autoSave.pendingChange = false;
-        } catch (err) {
+        } catch {
             // Save the editor content in LocalStorage as a last resort, just in case.
             try {
                 const saveKey = `draft-save-fail-${(new Date()).toISOString()}`;