[3.14] gh-142518: Define lock-free and per-object lock (GH-144548) (#144704)

gh-142518: Define lock-free and per-object lock (GH-144548)

- Add definitions of lock-free and per-object lock to the glossary
- Cross-reference these from list thread safety notes
- Change admonition to rubric
(cherry picked from commit 12dbae4c02dac197330d5bfa650b495e962aba6d)

Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>