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 section constructs a fake URL that doesn't really exist, and writes it into the logfile. We think it would be sufficient to say "Exporting resource list report from {pool_name} to {filename}" in the logfile.