remove unused test class

src/test/java/cz/vsb/fei/lab/AppTest.java

-package cz.vsb.fei.lab;
-
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
-import org.junit.jupiter.api.Test;
-
-/**
- * Unit test for simple App.
- */
-class AppTest {
-
-}