feat: add QR code generator and Nostr event handling

- Added the `simplesoftwareio/simple-qrcode` package to the project
- Created a new JavaScript file `nostrZap.js` to handle Nostr events
- Added the `nostrZap` function to the Alpine.js data property in `app.js`
- Updated the `services.php` configuration file to include the `nostr` environment variable
- Created a new database migration to add a `payment_event` field to the `einundzwanzig_plebs` table
- Made adjustments in the `Election:year.blade.php` view file to handle potential null values
- Updated `composer.lock` and `package.json` with the new dependencies

config/services.php

@@ -15,6 +15,7 @@ return [
     */
 
     'relay' => env('NOSTR_RELAY'),
+    'nostr' => env('NOSTR_P'),
 
     'postmark' => [
         'token' => env('POSTMARK_TOKEN'),