[Sprint: 38] XD-2123 Support for kerberized hdfs

There is no specific tests for kerberos other than I tested singlenode against
kerberized and non-kerberized hadoop instance.

- Modify hdfs.xml and hdfs-dataset.xml to read values
  via from hadoop.properties via property placeholder.
  This is needed for security config to kick in because
  reading properties properties-location in hadoop namespace
  is not enough. Default values for these are empty which
  gets normal hadoop configuration.
- Added same tweaks to shell's shdp namespace usage and
  added empty hadoop.properties file.
- Kerberized config is then enabled i.e. using below
  propertys in hadoop.properties:
  hadoop.security.authorization=true
  hadoop.security.authentication=kerberos
  dfs.namenode.kerberos.principal=hdfs/neo@LOCALDOMAIN
  yarn.resourcemanager.principal=yarn/neo@LOCALDOMAIN
  spring.hadoop.userKeytab=/usr/local/hadoops/janne.keytab
  spring.hadoop.userPrincipal=janne/neo
- Use of userKeytab and userPrincipal enables
  automatic login using kerberos keytab file.
created https://jira.spring.io/browse/XD-2364

We can do what was done in https://github.com/spring-projects/spring-xd/pull/1288 as an example...