Add Tomcat 7 and Jetty 8 samples

Switch the Tomcat 8 and Jetty 9 samples to Tomcat 7 and Jetty 8. Since
Tomcat 8 and Jetty 9 are now the default versions the previous samples
are no longer relevant, however, we do need integration tests to check
that we remain compatible with Tomcat 7 and Jetty 8.

See gh-1832

spring-boot-samples/spring-boot-sample-tomcat-jsp/src/main/resources/application.properties

@@ -0,0 +1,3 @@
+spring.view.prefix: /WEB-INF/jsp/
+spring.view.suffix: .jsp
+application.message: Hello Phil