Updated ImmutableFileTest.cpp in order to handle the fact that kXR_ChkLenErr has been removed in XRootD 5

Updated ImmutableFileTest.cpp in order to handle the fact that XrdCl::OpenFlags::Append has been removed in XRootD 5 as requested by CTA

Disk systems were not cleaned up from catalogue in system tests. This led to failure of tests against a persistent DB.

Also created a script to easily run the postgresql-backed DB unit tests outside of CI.

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.

- Type of checksumBlob in cta.proto should be bytes not string
- ADLER32 passed into blob as uint32_t not string (conversion to
  bytearray is now handled inside the ChecksumBlob class)

- Type of checksumBlob in cta.proto should be bytes not string
- ADLER32 passed into blob as uint32_t not string (conversion to
  bytearray is now handled inside the ChecksumBlob class)

Moved disk-operations-related code into the new "disk" directory

Added the creation of the directory corresponding to the vid of the tape to repack (xroot + local file system)