BATCHADM-160/BATCHADM-163 - Update Spring Batch Integration Documentation

* BATCHADM-160 - Update Spring Batch Integration Documentation
  - created initial version
  - use README.md for now as the documentation vehicle
  - https://jira.springsource.org/browse/BATCHADM-160
* BATCHADM-163 - Add documentation for namespace support
  - https://jira.springsource.org/browse/BATCHADM-163
BATCHADM-160 - Code review, rebased