Bug 24306: Add debug switch to koha-indexer

Bug 24306: Add debug switch to koha-indexer

This raises the debug level a lot, it it a bit overwhelming, but may be useful in debugging indexing issues

To test:
1 - Apply patches
2 - sudo koha-indexer --stop instance
3 - sudo debian/scripts/koha-indexer --start --debug instance
4 - tail -f /var/log/koha/instance/indexer-output.log
5 - Note you get a listing that nothign in the queue
6 - Go to staff client and make a change to a record
7 - Note the logs have tons of info

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>