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>
We don't think this should be in a try block. At the moment, if the file can't be opened or written to for some reason, the error is silently swallowed, and the action appears to have been successful.