MAPG-69 merge SignupController to LoginController and introduce Google login/sign up

mail/signup-noconfirm.html

@@ -0,0 +1,9 @@
+Hi,
+<br><br>
+You recently signed up on MapGuesser with this Google account ({{EMAIL}}).
+<br><br>
+Have fun on MapGuesser!
+<br><br>
+Regards,<br>
+MapGuesser<br>
+<a href="{{BASE_URL}}" title="MapGuesser">{{BASE_URL}}</a>

mail/signup.html

@@ -10,4 +10,5 @@ However if you want to immediately delete it, please click on the following link
 Have fun on MapGuesser!
 <br><br>
 Regards,<br>
-MapGuesser
+MapGuesser<br>
+<a href="{{BASE_URL}}" title="MapGuesser">{{BASE_URL}}</a>