utils::trimString() now returns an empty string if the string passed in parameter contains only white-space characters

Replaced the deprecated XrdClientUrlInfo by the XrdCl::URL object that is used for extracting a path of a file from a Xrootd URL

- 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)

The implemantation currently returns an empty disk system.

- 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)

This will prevent the process surviving during signal propagation time.

Refactored the async deletion of repack subrequests files via XRootD (used the xroot's async deletion)
Deleted the folder containing the repack subrequests files (Local file + XRootD)

The folder containing the files need now to be removed

We now have live (to be executed), failed and to be reported queues.
Archive jobs have all three types, retrieve jobs do not have a to be reported
queue. The RootEntry interface interface now provides the choice between the types.
All uses are currently hardcoded to LiveJobs.