Reduce the nodelock count for both cache and regular rbtdb (v9.16)
Increasing the nodelock count had major impact on the memory footprint in scenarios where multiple rbtdb structure would be created like hosting many zones in a single server.
This reverts commit 03446843 and sets the nodelock count to previously used values.
Backport of !5282 (merged)
Closes: #2829 (closed)
Edited by Michal Nowak