Added timeout feature for requests.

[d4rk-d4nph3]

Some of the sites I was testing was taking too much time by CloudFail. I traced out the culprit which was the Exception thrown:

Failed to establish a new connection: [Errno 60] Operation timed out'))

which occurs due to default timeout behavior used in requests. So, the process would be stuck on a particular subdomain request for a long time then resume after the exception is thrown.

This PR adds an optional timeout argument chosen by the user and also a default timeout of 5 sec if not given.

Hence, In this way CloudFail won't be stuck on any subdomain and also users will have the option to alter the timeout rather than the rigid hardcoded value.

Also, this makes the runtime of CloudFail to be near deterministic if everything goes right.