Remove long package names from samples

Long package names are really unnecessary in samples and they
just clutter things up. Also Spring Loaded doesn't work with
org.sfw packages, so to demo that technology you need a
different package name.

spring-boot-samples/spring-boot-sample-batch/src/main/java/sample/batch/SampleBatchApplication.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.sample.batch;
+package sample.batch;
 
 import org.springframework.batch.core.Job;
 import org.springframework.batch.core.Step;