Kapacitor 1.6.0 Release

[psteinbachs]

This epic tracks work scheduled for the Kapacitor 1.6 release. It will be considered functionally complete when the following are implemented:

• Zenoss Event Handler feat: Zenoss event handler #2484
• queryflux node queryflux kapacitor node. #2398
• Flux tasks side-by-side Add flux task executor to Kapacitor #2533
• A to function implementation

[timhallinflux]

#2478 -- would be a nice to have, if we address the key items and have time to add.

[docmerlin]

#2527