Add a monitoring container to KubePlus Pod

[devdattakulkarni]

There can be setups where Prometheus is running on the same cluster where KubePlus is installed.
For such setups, it will be good to have a monitoring container be part of KubePlus. Such a container will export a REST API that takes the Kind Name and instance Name as input and retrieves the metrics for it. For retrieveing the metrics, we will use kubectl metrics plugin.
Prometheus can be configured to probe this endpoint for the various application instances that will be created on the cluster.

[devdattakulkarni]

The monitoring container can also query opencost, when it is installed, to get the per app instance spend/cost amount.