Add standalone command line tool cta-tape-label.

Command mount, label, umount the tape pointed by VID option. Tape drive
and library parameters used from /etc/cta/TPCONFIG file and catalogue
parameters from /etc/cta/cta-catalogue.conf.
To be labelled the tape must be present in the catalogue and must be
empty.
By default the tool labels the tape with enabled logical block protection
if drive supports such mode. For non-blank tapes command checks previous tape
label and label only if the old label is the same or match to the label in the
command line oldLabel option. To skip label checks for non-blank tapes --force
option could be used.