More advanced Statistics and feedback

[eurodude]

In an effort to improve the MONARC experience for everyone, Statistics and maybe feedback.

Statistics on:

• time spent (extension of #71 )
• possibility to get an average of multiple analysis (not only stats for one)
• possibility to get an average of multiple instances for a given MONARC cloud

The goal here is that additional information can be made available to further improve security and awareness for a said instance or client network.