Bug 10703: Update stats table documentation

Bug 10703: Update stats table documentation

This patch updates the DB documentation for the statistics
table.

To test review the file and cofirm that documentation is there

Signed-off-by: Dobrica Pavlinusic <dpavlin@rot13.org>
Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>
(cherry picked from commit 7404b4f1775325ff8e72a3f9916a5c965e5ad151)
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>