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 think it would be better to use Messages for all strings, to allow them to be localised if necessary. Even if we think the translation will be the same in other languages, we might be wrong. For example, when we have "MTU" and "VLAN" below, are we sure that they will be written in the English way in all languages?