Implement Incremental crawling

[PROxZIMA]

Is your feature request related to a problem? Please describe.

Incremental Crawler visits a specific site multiple times in a specific interval of time. The main focus of an incremental crawl is to keep on updating the hyperlink list of a site whose content is being changed frequently. At every iteration, after the crawler visits such a site, the site’s “freshness” keeps on decreasing as time passes. Hence in the next iteration, the crawler updates the hyperlinks, resetting the freshness.

Describe the solution you'd like TODO

Describe alternatives you've considered TODO

Additional context TODO