Dashboards: Simplified PXC cluster dashboards

Problems to solve:

1. The current PXC Cluster dashboard is too complex for Developers or DBA without deep PXC knowledge. (We expect a lot of Developers to use it as a part of the DBaaS solution)
2. The dashboard is not providing  information about the structure of the dashboard 
3. No Actionable information for the user on the dashboard makes it less useful 

Proposed solution: 

1. develop an additional simplified dashboard for PXC cluster but keep the current ones for experts  (or modify them )

Here is the link of Product spec and please check the comments to see discussions.

https://docs.google.com/document/d/1Azt3q0SLVbbwmjAH4AMUPl8L0wjCjnpp2PBLopBvTQY/edit?usp=sharing