Bug 11021: Suppress unneeded fields in unimarc_complet default Framework

First patch, for "complete" framework, used by academic libray
900, 901, 910, 918, 920,950,960,970,980,987 fields were useless. I removed them.
I kept only the fields mentionned in Sudoc documentation http://documentation.abes.fr/sudoc/formats/loc/index.htm
916 field is not cited in that page, but it belongs to Sudoc format.

I kept also 2 fields specific to Electre in 2013 :
902 niveau de lecture (Electre)
903  indexation (Electre)

I also added to the name of the 9XX fields I kept the mention (Sudoc) / (Electre) / (Koha), so it could be easier for librarians to know what is the purpose and the origin of each field

I don't make an updatedatabase, because some libraries could still be using these fields for good or bad reasons.

To test :
1) take a fresh Koha with unimarc marcflavor
2) in web installer, select french language, unimarc marflavor and "Grilles de catalogage complètes".
3) check default framework in Administration > MARC Frameworks : it should be without 900,901,910,918,920,950,970,980,987

Signed-off-by: Gaetan Boisson <gaetan.boisson@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>