[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.
I'll try to see if for shdp 2.1.0.RC1 we can do some tweaks so that we could simply use `hadoop.properties` without having a need for property placeholder.