Bug 21846: (follow-up) Add maintenance script

Bug 21846: (follow-up) Add maintenance script

This patch adds a maintenance script that generates the missing
tags_approval entries based on the tags_all table, and then recalculates
the weights for both tags_approval and tags_index tables.

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit 293eee9959925397e4fdc84ae0d4baea2cf7d94c)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>