MAPG-164 show application's name from env variable

mail/signup-noconfirm.html

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