text: Title: Add IQR Anomaly Detector
  Body: **Is your feature request related to a current problem? Please describe.**
  I'd like to detect outliers using the Interquartile range (IQR) method, i.e. an outlier is a point that lies more than 1.5 * IQR above(below) the upper(lower) quartile
  
  **Describe proposed solution**
  Similar to the QuantileDetector but use calculation IQR = (Q3-Q1) where Q1 and Q3 are the 25th and 75th quartiles. Then set the upper fence at Q3 + 1.5*IQR and the lower fence to Q1 - 1.5*IQR
  
  **Describe potential alternatives**
  I'm not aware of any alternative.
  
  **Additional context**
  
  