Extensions: Added pg_stat_monitor

[LenzGr]

pg_stat_monitor provides improved insights that allow database users to understand query origins, execution, planning statistics and details, query information, and metadata.

This significantly improves observability, enabling users to debug and tune query performance. pg_stat_monitor is developed on the basis of pg_stat_statements as its more advanced replacement.

Signed-off-by: Lenz Grimmer [email protected]