Add namespaces as a top level resource in the Web UI
This PR does the following:
- Replace the deployments table in the service mesh page with namespaces
- Add a Namespaces index page that lists all namespaces and their stats
- Add an individual namespace page showing all resources for that namespace
- Make the incomplete mesh message more generic to any resource type
- Revamp rest of service mesh page to move off ListPods
Risha Mars