Request to add document about the derived data feature about primihub-docs

[fzs666888]

There are multiple parties (different physical locations) in the data table used in federated learning and multi-party security computing, so it is necessary to conduct data intersection of multi-party multi-data table and align ID or feature at one time. Derived data is a virtual fusion data set generated after data intersection, alignment and feature pulling by multiple parties.

[fzs666888]

role：
Optimize data to improve efficiency. Initiate tasks based on derived data to save data processing time