Deleted the checking of the presence of non superseded files during an Archive Mount.

Fixed.

Replaced the map of tape files with a list as the assumption that we have one copy per copyNb is no more valid with repack.

Added a check while mounting a tape for writing : if some tape files located in the writing tape are not superseded by others,
the write session will fail.

Note: The test CatalogueTest.exist_non_superseded_files_after_fseq is supposed to fail.

Harmonized the copyNb type to uint32_t
Corrected a bug in RetrieveQueue::getContainerSummary() --> After insertion in the queue, the number of files and bytes added were equal to 0.

CatalogueTest now asserts new archive file identifiers are unique as opposed to strictly incrementing sequentially by 1

Woah!  Got carried away with const.  This commit Removes the const
qualifier from the ArchiveFileItor::next() method because next()
modifies the iterator.

To loop through an ArchiveFileItor:

  auto itor = catalogue.getArchiveFilesForRepackItor(vid, startFSeq);
  while(itor.hasMore()) {
    const auto archiveFile = itor.next();
    // Do something with archiveFile
  }

Added MEDIA_TYPE and VENDOR columns to TAPE table and upgraded xrootd-ssi-protobuf-interface to v0.29

Catalogue::PrepareToRetrieveXXXX() methods now throw UserError exceptions if the tapes involved are disabled.  The error message is now clearer: 'No tape files available for archive file with ...