public static void registerRocksDBTableFormatConfig(final Class<?> cls, final BlockBasedTableConfig cfg) {
        registerRocksDBTableFormatConfig(null, cls, cfg);
    }
Users can register a custom rocksdb BlockBasedTableConfig, then the related
classes will get their options by the key of their own class name.  If
the user does not register a config, a default config will be provided.

@param cls the key of BlockBasedTableConfig
@param cfg the BlockBasedTableConfig
jraft-core/src/main/java/com/alipay/sofa/jraft/util/StorageOptionsFactory.java