coll/scripts: Use autodie completely

Signed-off-by: Niels Thykier <niels@thykier.net>
coll/scripts: Refactor and reuse shebang line extraction

Signed-off-by: Niels Thykier <niels@thykier.net>
coll/scripts: Replace bareword file handles

Signed-off-by: Niels Thykier <niels@thykier.net>