Bump Tomcat startup/shutdown to 2.5s each

The StringCalculatorServletTests are failing in CI with:

> java.io.IOException: HTTP/1.1 header parser received no bytes

- https://github.com/mbland/tomcat-servlet-testing-example/runs/18323944457

Bumping up the setup and teardown times should get this passing again.
Of course, it unconditionally slows down local development as well. I
may either use this as a teaching point, or try to conditionally set
different timeouts for each environment.

strcalc/src/test/java/com/mike_bland/training/testing/tomcat/StringCalculatorServletTest.java

@@ -35,12 +35,12 @@ class StringCalculatorServletTest {
 
     @BeforeAll
     static void setUpClass() throws Exception {
-       tomcatUri = tomcatServer.start(1000);
+       tomcatUri = tomcatServer.start(2500);
     }
 
     @AfterAll
     static void tearDownClass() throws Exception {
-        tomcatServer.stop(250);
+        tomcatServer.stop(2500);
     }
 
     HttpRequest.Builder newRequestBuilder(String relPath) {