LP#1931737: Allow the delay of symspell updates

LP#1931737: Allow the delay of symspell updates

This commit adds a new internal flag, auto-created at the time of need,
to control whether record ingest will cause immediate updates to the
symspell dictionary, or if those updates will simply be recorded for
later incorporation.  Inline symspell dictionary updates can cause
record updates to be logically serialized, impacting the preformance of
other tools used for batch reingest.

pingest.pl is changed to allow an administrator to make use of this
feature via the --delay-symspell command line flag.

Signed-off-by: Mike Rylander <mrylander@gmail.com>