Add v1 dashboard

[zmalik]

This PR:

• adds a v1 dashboard and removes SLA and adds HEALTH section
• all dashboard uses namespace in their queries so we don't mix different namespace metrics. Move cluster above datacenter variable
• adds a simple workload.yaml file to test with kubectl kudo install cassandra in default namespace

Dashboard:

[porridge]

Please consider varying the colors between the heap/CPU/disk/... graphs. This provides a sub-conscious visual cue about which graph is which - after some usage the brain learns which graph is which and does not need to spend time reading the descriptions to remember.

I have a graph like this on my desktop panel and can vouch for the value of this convention:

[zmalik]

thanks @porridge I think this is a great idea and I will update the dashboard