Fix http ntlm proxy in bruteforce module

[D00Movenok]

Previously, the brute force module used a proxy only in the autodiscover request, now it uses a proxy in every authentication request.

[staaldraad]

hey @D00Movenok , thanks for the PR and apologies for only getting around to it now. I haven't been monitoring this repo.

I had to do a rebase to fix some conflicts introduced by #145 but this looks good to go now. Thanks for the contribution!