Support numeric Quantiles

[mikeldking]

• [ ] min / max
• [ ] p1/p99
• [ ] p75/p25
• [x] mean

{
   node(id: foo) {
       ... on Dimension {
          p1: dataQualityMetricTimeSeries(metric: p1)
          p1: dataQualityMetricTimeSeries(metric: p1)
       }
   
   }
}