- 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

(this is preliminary, more work remains)

support a separate cached connection for binds when using (liberal) idassert flagged with "override" (ITS#4781)

starttls
tls keywords
logbase
logfilter
syncdata

parameters that are now available.  Add the relevant documentation from
slapd.conf(5) about these parameters.