[FEATURE] Resend confirmation emails

[jdabtieu]

Is your feature request related to a problem? Please describe.

Sometimes a confirmation email doesn't get received the first time and people request a second confirmation.

Describe the solution you'd like

• An admin button on the users page to force verify
• Also, when logging in to an unverified account, a button to resend email
• should only resend if at least a minute has passed since last one
• delete unverified accounts after a week, with daily tasks

Describe alternatives you've considered

The current way is to hop into a Python + sqlite shell to do it manually

Additional context

We want something like this (derived from /register):

@app.route("/register", methods=["POST"])
@admin_required
def resend_register_confirmation():
    user_id = request.form.get("user_id")
    if not user_id:
        flash("Must provide user ID", "danger")
        return redirect("/admin/users")

    user = db.execute("SELECT * FROM users WHERE id=:id", id=user_id)

    if len(user) == 0:
        flash("That user doesn't exist", "danger")
        return redirect("/admin/users")
    if user[0]["verified"] == 1: # or whatever this was called
        flash("User is already verified", "danger")
        return redirect("/admin/users")

    token = create_jwt({'email': user[0]['email']}, app.config['SECRET_KEY'])
    text = render_template('email/confirm_account.html',
                           username=user[0]['username'], token=token)

    if not app.config['TESTING']:
        send_email('CTFOJ Account Confirmation',
                   app.config['MAIL_DEFAULT_SENDER'], [email], text)

    flash('Email sent!', 'success')
    logger.info((f"User #{session['user_id']} ({session['username']}) has initiated another "
                 f"registration request for user #{user_id}"), extra={"section": "auth"})
    return redirect("/admin/users")

[jdabtieu]

Completed via 55682a7