Add configuration for adjusting URL crawling order

[marevol]

A new configuration setting (config.crawl.order) has been added to control the order in which URLs are processed during crawling. This setting allows for either "sequential" or "random" processing. By default, URLs are processed sequentially. To enable random ordering, set the config.crawl.order configuration parameter to “random” in the CrawlingConfig class. This modification affects the FessUrlQueueService class to implement the URL processing order based on the specified configuration.