MAPG-69 implement sign up functionality

mail/signup.tpl

@@ -0,0 +1,13 @@
+Hi,
+
+You recently signed up on MapGuesser with this email address ({{EMAIL}}). To activate your account, please click on the following link:
+<a href="{{ACTIVATE_LINK}}" title="Account activation">{{ACTIVATE_LINK}}</a>
+
+If you did not sign up on MapGuesser or changed your mind, no further action is required, your email address will be deleted soon.
+However if you want to immediately delete it, please click on the following link:
+<a href="{{CANCEL_LINK}}" title="Sign up cancellation">{{CANCEL_LINK}}</a>
+
+Have fun on MapGuesser!
+
+Regards,
+MapGuesser