Rename server.address to my-server.address across properties files and LoginController for consistency and clarity.

backend/src/main/java/com/alttd/altitudeweb/controllers/login/LoginController.java

@@ -36,7 +36,7 @@ public class LoginController implements LoginApi {
     @Value("${login.secret:#{null}}")
     private String loginSecret;
 
-    @Value("${server.address:#{null}}")
+    @Value("${my-server.address:#{null}}")
     private String serverAddress;
 
     private record CacheEntry(UUID uuid, Instant expiry) {}