Migrate notes_meta file_id to bigint

[juliusknorr]

int(11) is too small, we should use bigint for any file id referencing column:

CREATE TABLE `oc_notes_meta` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `file_id` int(11) NOT NULL,
  `user_id` varchar(64) NOT NULL,
  `last_update` int(11) NOT NULL,
  `etag` varchar(32) NOT NULL,
  `content_etag` varchar(32) NOT NULL,
  `file_etag` varchar(40) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `notes_meta_file_user_index` (`file_id`,`user_id`),
  KEY `notes_meta_file_id_index` (`file_id`),
  KEY `notes_meta_user_id_index` (`user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=5518 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin ROW_FORMAT=COMPRESSED;