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.

Also organised common in subdirectories, and added sub directory for mockDB.

Added the unique pointer for sqlite statements with custom deleter and fixed the error reporting for SQLite prepare

License comment is no longer filtered out by doxygen when generating web pages of the individual source files.

Created AdminUsersList in the object store as a first step to implement an object store middle tier.
Some namespace fixes for unit tests.

Implemented the new interface on the Rados backend.
Fixed several bugs.