added support for KDC proxies to asktgt, asktgs and s4u

[0xe7]

As requested by MichaelGrafnetter in issue #100. asktgt, asktgs and s4u can now be used through a KDC proxy using the /proxyurl:URL argument. If the /proxyurl argument isn't passed, Rubeus should behave as before. An example of using it to request a service ticket:

C:\Rubeus>.\Rubeus.exe asktgs /service:ldap/idc1.internal.zeroday.lab /nowrap /proxyurl:https://192.168.71.40/kdcproxy /ticket:doIFtDCCBbCg...mFsLnplcm9kYXkubGFi

   ______        _
  (_____ \      | |
   _____) )_   _| |__  _____ _   _  ___
  |  __  /| | | |  _ \| ___ | | | |/___)
  | |  \ \| |_| | |_) ) ____| |_| |___ |
  |_|   |_|____/|____/|_____)____/(___/

  v2.0.2

[*] Action: Ask TGS

[*] Requesting default etypes (RC4_HMAC, AES[128/256]_CTS_HMAC_SHA1) for the service ticket
[*] Building TGS-REQ request for: 'ldap/idc1.internal.zeroday.lab'
[*] Sending request via KDC proxy: https://192.168.71.40/kdcproxy
[+] TGS request successful!
[*] base64(ticket.kirbi):

      doIF/DCCBfigAwIBBaE...nplcm9kYXkubGFi

  ServiceName              :  ldap/idc1.internal.zeroday.lab
  ServiceRealm             :  INTERNAL.ZERODAY.LAB
  UserName                 :  internal.user
  UserRealm                :  INTERNAL.ZERODAY.LAB
  StartTime                :  27/01/2022 23:32:21
  EndTime                  :  28/01/2022 09:32:21
  RenewTill                :  04/02/2022 23:21:42
  Flags                    :  name_canonicalize, ok_as_delegate, pre_authent, renewable, forwardable
  KeyType                  :  aes256_cts_hmac_sha1
  Base64(key)              :  Y9MGx/TY77PBNMxo+z+3etq1fRSl2JPa4L1PlUlPhnU=

[HarmJ0y]

👍 landed