Add the base files for the splunk role.
Prepare template files for splunk.
Add the basic splunk role.
Make sure users in the syslog group can read the log files.
Ensure that nginx folder and its content is readable by the syslog group.
Update to add splunk to all machines.
Move overridable defaults to the top of the file.
Use get_url and a handler to restart splunk.
Splunk has to be started once to generate some files.
Allow instances to reach splunk server.
Merge pull request #310 from edx/feanil/splunk_role

Feanil/splunk role
Merge branch 'master' into jarv/provision