title: Filter the Jenkins executor list to only the active ones
body: <p>The company I work for uses a large Jenkins server with a large number of slaves to handle the build and testing for a particular product.  The large number of slaves, many with numerous executor slots, makes for a very long list of slaves/executors in our typical Jenkins view.</p>
  
  <p>Many users have asked if this view could be compressed, down to just a list of slaves with only those executors that are active appearing.  For example; assume that Slave A has 2 executors, both idle and Slave B has 2 executors, one active.  The display would look like this:</p>
  
  <p>Slave A (2 available)
  Slave B (1 available)
    1: Building Job A</p>
  
  <p>Instead of the typical view (using the same example):
  Slave A
    1: Idle
    2: Idle
  Slave B
    1: Idle
    2: Building Job A</p>
  
  <p>I search for a plugin that would do this, or any native behavior, but didn't see anything like this.  Does anyone know if it is possible and if so, how?</p>