Features/flot thresholds (#2412)
Features/flot thresholds (#2412)

* Thresholds draft

* Make generated thresholds unique

* Code refactoring

volodymyr-babak/thingsboard,volodymyr-babak/thingsboard,thingsboard/thingsboard,volodymyr-babak/thingsboard,thingsboard/thingsboard,thingsboard/thingsboard,thingsboard/thingsboard,volodymyr-babak/thingsboard,thingsboard/thingsboard,thingsboard/thingsboard,volodymyr-babak/thingsboard,volodymyr-babak/thingsboard