Add user verification

[yurihnrq]

Description

Send verification e-mail with token to user on account creation. Create and endpoint (users\:userId\verify) to confirm verification.
A new property should be added to the User model: isVerified.

Tasks

• Create EmailProvider interface and implement it with Nodemailer.
• Create SendVerificationEmailService.
• Send verification e-mail at CreateUserController.
• Create users\:userId\verify route and VerifyUserController.