Bug 6149: Follow-up [defaults] - Stopwords for Result Highlighting

Bug 6149: Follow-up [defaults] - Stopwords for Result Highlighting

- changed sample words to and|or|not in sysprefs.sql and
  updatedatabase
- changed systempreference name from OpacHighlightedStopwords
  to HighlightedStopwords, as it also works for the staff
  results page

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>