Standardize Build

The build now uses spring build conventions to simplify the build

Fixes gh-4284

samples/xml/helloworld/spring-security-samples-xml-helloworld.gradle

@@ -0,0 +1,13 @@
+apply plugin: 'io.spring.convention.spring-sample-war'
+
+dependencies {
+	compile project(':spring-security-config')
+	compile project(':spring-security-web')
+	compile jstlDependencies
+	compile slf4jDependencies
+	compile 'javax.servlet.jsp:javax.servlet.jsp-api'
+
+	providedCompile 'javax.servlet:javax.servlet-api'
+
+	integrationTestCompile gebDependencies
+}