Show node number in clusters page

Problem

As a user, when I review the list of clusters in my Group/ Project, I an not able to see any information regarding the number of nodes or the integration status.

Proposal

Adding the number of nodes and integration status would help a developer decide which cluster is suitable for their application needs and an operator get an overview of the Kubernetes available infrastructure (a view that could be enhanced by resources usage per cluster in a different issue).

Design proposal