[feat] 2 Stage Cooling

[dgoodwin430]

@swingerman thanks for building this integration!

Is it possible to run 2 stage cooling just like you have implemented 2 stage heating?

Below is my code and I am using a an automation to control the switching valve until the heat_cool_reverse_entity is implemented.

climate:
  - platform: dual_smart_thermostat
    name: Study
    heater: input_boolean.heatpump1heat
    cooler: switch.heatpump1
    #heat_cool_reverse_entity: switch.heatpump1valve
    secondary_heater: switch.heatpump1stage2
    secondary_heater_timeout: 00:00:30
    secondary_heater_dual_mode: true
    target_sensor: sensor.apollo_msr_1_974fdc_bme280_temperature
    min_temp: 40
    max_temp: 90
    heat_cool_mode: true # <-required
    ac_mode: true
    initial_hvac_mode: "heat_cool"
    target_temp: 70
    target_temp_low: 65
    target_temp_high: 75
    cold_tolerance: 0.3
    hot_tolerance: 0
    min_cycle_duration:
      seconds: 5
    keep_alive:
      minutes: 3
    precision: 1.0