[Charts] Support plain, non bucketed data

Currently we only support bucketed data in Hawkular Charts, but we can also fetch unbucketed data directly from Hawkular Metrics.

Unbucketed data is in a different format (just a timstamp and value) which means it cannot be directly consumed by the charts.

Its fairly simple when a client is directly handling data, to just look through the non-bucketed data and just set things like avg,min,max to the actual datapoint value. Once they do this, the data can be consumed and graphed by charts.

It may be a good idea to allow charts to directly handle non-bucketed data.