- fix various connection creation/setup concurrency issues
- use shared connection when always idasserting (similar to ITS#4781)
- reduce the impact of schema mapping when not used (tnx to gprof)
- fix temporary/tainted connection leak in abnormal conditions

add "report" to "onerr" modes: continue a search in case one target returns an error, and only propagate the error at the end

fix several minor issues with using dangling pointers and uninitialized data
fix caching of privileged connections
fix issues with unresponsive target failures during search

fix concurrency issue when binding before a search; rework and cleanup data structures (remove unused members)

Better logging for tracing

Note: this breaks LDAP_COMP_MATCH and SLAP_ZONE_MALLOC. But they
were probably broken already anyway.

give slapd a chance to play callback cleanup handlers when a search operation is abandoned (ITS#4645)