apache frontend: fix typo and use "frontend administrators" instead of "the frontend administrator"

software/apache-frontend/instance-slave-apache-input-schema.json

@@ -132,14 +132,14 @@
 
     "apache_custom_http": {
       "title": "HTTP configuration",
-      "description": "Raw http configuration in python template format. Your site will be rejected if you use it without notification and approval of the frontend adminastrator",
+      "description": "Raw http configuration in python template format. Your site will be rejected if you use it without notification and approval of frontend administrators",
       "default": "",
       "textarea": true,
       "type": "string"
     },
     "apache_custom_https": {
       "title": "HTTPS configuration",
-      "description": "Raw https configuration in python template format. Your site will be rejected if you use it without notification and approval of the frontend adminastrator",
+      "description": "Raw https configuration in python template format. Your site will be rejected if you use it without notification and approval of frontend administrators",
       "default": "",
       "textarea": true,
       "type": "string"