Correct how GenOO becomes aware of a new db column in annotate_db_sample_with_deletions.pl

Previously DBIx::Class and GenOO were becoming aware of the new
database column "deletion" in an obscure way. The code now is much
cleaner. Also the updates are now done in batch in a single db
transaction. This should improve performance and stability.
Use cigar string to identify deletions -> huge performance improvement.

The script annotate_db_sample_with_deletions.pl was using GenOO methods
to identify deletions. Instead now it looks directly in the cigar
string which is a db column and therefore the update is extremely
faster