Custom Captcha like verification #1094

I know there's already a Captcha issue (#911) but this one takes it to the next level, making it so server mods can abuse it,

Required permissions for the Mod: MANAGE_GUILD
Required permissions for the Bot: MANAGE_MESSAGES, SEND_LINKS and MANAGE_ROLES
Command name/aliases: customcaptcha, advancedcaptcha, captcha+, captchap

Usage: <prefix>captcha <(#channel or [0-9]channel)> <(@role or [0-9]role)>
Bot would then ask for acceptable replies separated by comma.

In action example:

Moru Zerinho6 - s!customcaptcha #verify-yourself @ verified

Switchblade - Defined captcha channel to #verify-yourself.
Now send acceptable replies separated by comma and a space.

Moru Zerinho6 - two, 2, arroz, I read the rules and agree that I will follow them from now on

Switchblade - Great, users that type two, 2, arroz or I read the rules and agree that I will follow them from now on, on #verify-yourself, will be given the @ verified role

Note: I separated the @ with verified because I was actually going to mention a user with the user name called virified