Replace column failed_iuid VARCHAR(4000) by completeness INTEGER in study and series table

[gunterze]

alter table study add completeness int4;
alter table study drop failed_iuids;
alter table series add completeness int4;
alter table series drop failed_iuids;

• avoid problems with DBs concerning indexing large VARCHAR columns
• allow to distinguish between unknown completeness (=0) and known incompleteness (=1) caused by failed retrieves from the Fallback C-Move SCP without having to consider also column failed_retrieves

public enum Completeness {
    UNKNOWN, PARTIAL, COMPLETE
}