plugins: Add opencost plugin

[yolossn]

How to install opencost in cluster

1. Install prometheus using helm

   helm repo add prometheus-community https://prometheus-community.github.io/helm-charts helm install prom prometheus-community/kube-prometheus-stack

2. Create a values.yaml

   opencost:
   prometheus:
   internal:
     enabled: true
     namespaceName: default
     port: 9090
     serviceName: prom-kube-prometheus-stack-prometheus

3. Install opencost

   helm repo add opencost https://opencost.github.io/opencost-helm-chart helm install -f values.yaml my-opencost opencost/opencost

https://github.com/headlamp-k8s/plugins/assets/22731013/6aba7f18-3927-4ebb-8bbb-dc6fb721efba

[yolossn]

Adding few screenshots for reference.

[yolossn]