CP-8866:Develop for Resource Statistic Feature on XenCenter

Based on the requirements draft and discussed solution, develop the prototype for Resource Statistic Feature part on XenCenter, that is, provide the export to Excel and CSV functionality with required data sets,by accessing the XenCenter cache.
Signed-off-by: Cheng Zhang <cheng.zhang@citrix.com>
This reports the host name if the VM is running, but the pool name if it is Halted. But the pool name is always the same because the report only outputs one pool. So I think it would be clearer to call this column "Running On", and list the resident_on host name if it is present, but a hyphen if there is no resident_on.