Adding pagination to the API

[JoshuaMart]

Hi,
I could notice that in the case of important scopes, the use of Chaos in Amass simply makes the tool crash due to an excessive consumption of memory.

I think this is partly due to the lack of pagination. In general this would be a useful addition. For example, with the domain `army.mil, a 65MB response for 2 493 133 results is returned (not even 1% of the results seem to be alive).
So in general, even with other tools there are performance issues.

So I think it would be nice to have a pagination system either fixed or with a limit to return a certain number of results.

Regards