* Add GetMemoryInventory command to CATEGORY_COMMANDS_ALL['Systems']
* Add elif command == GetMemoryInventory to Systems category, to use forthcoming get_memory_inventory() function from redfish_utils
* Add get_memory_inventory() function to redfish_utils.py, which does not include any Absent dimms
* Remove trailing whitespace
* Add get_multi_memory_inventory() function to aggregate get_memory_inventory
* Call new function get_multi_memory_inventory()
* Add memory example in docstring
* Fix comment referring to CPUs instead of DIMMs