Add sample script for extracting Confluence and JIRA backups

This is an example of how to extract Confluence and JIRA backups from:
1. A remote server running Confluence/JIRA
2. A tarball
3. A Clonezilla image

Please read and customize the script to fit your specific requirements.

Signed-off-by: Gianpaolo Macario <gmacario@gmail.com>