Improve nxshell repostats command to display versions and proxies count

Repostats command don't display the number of versioned documents neither the number of proxies, this make difficult to understand other number like total export or import documents.

For instance we can add to the output:

Number of versioned documents: (SELECT COUNT FROM Document WHERE ecm:isCheckedInVersion=1)
Number of proxies: (SELECT COUNT FROM Document WHERE ecm:isProxy=1)
Number of document marked as deleted: XXX
Total documents and versions: XXXX