Add "Resend confirmation e-mail" link in profile settings

Adds a convenience link to resend the confirmation e-mail if necessary. Before, user had to logout or open an Incognito Window to do this.

Screenshot:

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/700e6d98e1c5b58726fbed4e52a09c06/image.png)

Fixes https://github.com/gitlabhq/gitlabhq/issues/9274

See merge request !634