Added missing GLUE2 attributes and max/defaults values.

- GLUE2ComputingShareMaxMainMemory (rss)
- GLUE2ComputingShareMaxVirtualMemory (vmem)
- GLUE2ComputingShareMaxSlotsPerJob (and GLUE equivalent)
- GLUE2ComputingShareDefaultWallTime
- GLUE2ComputingShareDefaultCPUTime
- GLUE2ComputingShareMaxTotalJobs
- GLUE2ComputingShareMaxWaitingJobs


This change addresses:
https://savannah.cern.ch/bugs/index.php?95183
https://ggus.eu/?mode=ticket_info&ticket_id=104815
https://ggus.eu/?mode=ticket_info&ticket_id=82902
https://ggus.eu/index.php?mode=ticket_info&ticket_id=97721
https://ggus.eu/?mode=ticket_info&ticket_id=102416