Allow DOAS over-sizing for air-side economizing

[mdahlhausen]

Allow oversizing DOAS systems to provide air-side economizing.

Oversizing the system by 30% is common for LEED. Consider an added argument for system oversizing applied to terminal units and the main air loop. Some free-cooling is already done with the default OAT reset.

[jiangithub]

If the scope is for the DOE prototype models to meet minimum code requirements (90.1), there is nothing to trigger over sizing DOAS.
For high-efficiency building design, it is building specific. If the space conditioning HVAC allows OA intake, such as a retail building served by RTUs for load and an DOAS for ventilation, the RTUs can have economizer and the DOAS doesn't need to be oversized.
Therefore, such feature should not be added as a standard feature even for high-efficiency building design. The current Create Prototype Model measure doesn't support customization and the users won't have a way to customize this feature. Therefore, I don't see how this is going to be useful.

[mdahlhausen]

@jiangithub This is for the zne hvac system measures, and would only be used with those templates. I'd implement it in the air loop controls / efficiency methods for the zne templates only.

Oversizing DOAS systems is common design choice for newer zne offices and other large buildings that use zone conditioning systems without outdoor air and a centralized DOAS system.