Adds the sync-optimizer tool for https://jira.duraspace.org/browse/DURACLOUD-877. This tool determines the optimal number of threads to use with the SyncTool.

Also replaces springsource version of commons-io with central version across projects. This was required because the sync-tool-optimizer was picking up the earlier springsource version classes, which didn't allow for the use of features in the newer commons-io versions.