Implement dual maximum constant volume heating control logic for VAV box with reheat

[AntoineGautier]

Refactor Buildings.Examples.VAVReheat.Controls.RoomVAV to allow the following control logic.

(Note that the current single maximum logic can still be represented by setting the minimum air flow equal to the heating air flow.)

This is needed because the comparison between ASHRAE2006 and Guideline36 shows (see figure below based on the master branch commit 0ef82ef)

• a high outdoor air flow rate ratio for ASHRAE2006: this is addressed by Minimum outdoor air flow control in Examples.VAVReheat  #2019,
• a high supply air flow rate ratio for ASHRAE2006: this is due to the minimum discharge flow rate of the terminal units.

Note that the outdoor air flow rate ratio is frequently below the minimum (0.3 for ASHRAE2006). This is due to:

• the minimum TMix control in ASHRAE2006,
• the high integral time values used in both models for the minimum outdoor air control (600s for ASHRAE2006 and 1200s for Guideline36). See below for the impact on a week of June for ASHRAE2006 when the control switches from economizer cooling to minimum outdoor air: it takes 2-3h for the economizer to reach the outdoor air set point.

The issue related to the high integral is addressed in #2030 for both models.

[AntoineGautier]

This is addressed in branch issue2028_dualMin which includes the commits from #2030

[AntoineGautier]

The impact of the above changes have been assessed with annual simulations of the models in Buildings.Examples.VAVReheat.

Branch issue2028_dualMin (commit 406e164)

.. table:: Heating, cooling, fan and total site HVAC energy, and savings of guideline 36 case versus base case.

   ===================================== ===================================== ====================================== ====================================== =====
   :math:`E_{h} \quad [kWh/(m^2\,a)]`    :math:`E_{c} \quad [kWh/(m^2\,a)]`    :math:`E_{f} \quad [kWh/(m^2\,a)]`     :math:`E_{tot} \quad [kWh/(m^2\,a)]`     [%]
   ===================================== ===================================== ====================================== ====================================== =====
                                   5.581                                 16.47                                  2.299                                  24.35   
                                   3.643                                 14.67                                  1.877                                  20.19  17.0 
   ===================================== ===================================== ====================================== ====================================== =====
  
  
CPUtime, base 53'
CPUtime, G36  94'

Branch issue2019_VAV_MinOA (commit d32b474)

.. table:: Heating, cooling, fan and total site HVAC energy, and savings of guideline 36 case versus base case.

   ===================================== ===================================== ====================================== ====================================== =====
   :math:`E_{h} \quad [kWh/(m^2\,a)]`    :math:`E_{c} \quad [kWh/(m^2\,a)]`    :math:`E_{f} \quad [kWh/(m^2\,a)]`     :math:`E_{tot} \quad [kWh/(m^2\,a)]`     [%]
   ===================================== ===================================== ====================================== ====================================== =====
                                   6.147                                 18.04                                  2.385                                  26.57   
                                   3.643                                 14.67                                  1.877                                  20.19  24.0 
   ===================================== ===================================== ====================================== ====================================== =====
  
  
CPUtime, base 52'
CPUtime, G36  95'