Issue #3495842 - Add permissions

live_css.permissions.yml

+live css save data:
+  title: 'Save data'
+live css manage settings:
+  title: 'Manage live CSS settings'

live_css.routing.yml

@@ -3,7 +3,7 @@ live_css.save:
   defaults:
     _controller: '\Drupal\live_css\Controller\LiveCSSController::cssSave'
   requirements:
-    _permission: 'edit css'
+    _permission: 'live css save data'
 
 live_css.admin:
   pattern: '/admin/config/development/live_css'
@@ -11,4 +11,4 @@ live_css.admin:
     _form: '\Drupal\live_css\Form\LiveCSSAdmin'
     _title: 'Live CSS administration page.'
   requirements:
-    _access: 'TRUE'
+    _permission: 'live css manage settings'