New enhancement to the migration part of CASTOR. In particular :

  - svcClass was dropped from the MigrationRouting table as unused. Tools have been amended accordingly.
  - MigrationJob has now an originalCopyNb and originalVID in case of repack migrations that allow to identify repacks properly
  - a table MigratedSegment has been added holding information on other existing tape segments for the migrating files. This allows to avoid putting 2 copies on a file on the same tape
  - in general, migrations that can be triggered at recall time (extra copy and repacks) are populated in MigrationJob table from the beginning, in status MIGRATIONJOB_WAITONRECALL. This allows easy triggering of the migrations after the recall and to identify any problematic migration routing before we even recall.