Feature bulk crawl

[grumpyp]

Hello,

I would like to contribute and add a bulk crawl function.

It would use multiprocessing to optimize the crawling duration.
The user can add the desired domains to a list in the file and execute it with the CL.

If needed I will also enable a text file, where the user adds all the domains.

@amitupreti: Please provide feedback

[hellobd]

@grumpyp, great, waiting for the your contribution, in the CSV , along with URls where the email were found would make the project rich