Add missing indices in post-upgrade script

nextcloud-occ db:add-missing-indices should be run. This will result in a short db load increase

Probably a good idea to run the other db helpers as well:

  db:add-missing-columns                 Add missing optional columns to the database tables
  db:add-missing-indices                 Add missing indices to the database tables
  db:add-missing-primary-keys            Add missing primary keys to the database tables