Partial fix for fdo#80338: help for calc statistics

Entry page for Calc Data statistics. This is work in progress and the help content should be completed with the correct information.

Change-Id: I34f67a2b10d76bb1da6a9b9f4e24d4242396cbe4
Reviewed-on: https://gerrit.libreoffice.org/10703
Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>