@ mention of reviewers`

@Didayolo @ObadaS`

A brief description of the purpose of the changes contained in this PR.

Now users can resend account activation emails if they haven't received the link or the link is expired.

Resend activation link screen (http://localhost/accounts/resend_activation/)

When user clicks the activation link and it is expired, they are taken to this screen automatically

user enters wrong email in the activation sceen

user enters email that is already activated

user enters correct email (not activated). user is taken to home page with this message

update wiki to mention this feature for users who have lost the link and can use this to resend the link