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>
Does RelatedTask have a purpose? We can't understand why it's there, given that there is no task taking place on the server. We tried commenting it out, and the progress bar still proceeded correctly on the Events view, and the report was generated as usual.