[feature] Add a new processor plugin for "whois" information

[dgtlmoon]

Now that #1941 makes everything cleaner, we can go back to solving pluggable 'processors', a new one could be "whois" plugin

https://github.com/richardpenman/whois

this would just take the domain-name from the URL and pass it to the whois-processor, probably these should live as separate pypi packages

changedetectionio-whois or something could be nice

[marleyjaffe]

This would be helpful!