Add support for Refrigeration Systems

[chriswmackey]

It seems like we should add support for this and it should function similarly to how HVAC and SHW systems function in the schema. Actually, it might be best to just enable people to swap out the HVAC with a refrigeration system template. Then, we can parse in the walk-in refrigerators that are in the standards gem as Program Types and the refrigeration system will just try to meet their cold setpoints:

https://github.com/NREL/openstudio-standards/blob/master/lib/openstudio-standards/standards/ashrae_90_1/ashrae_90_1_2019/data/ashrae_90_1_2019.refrigeration_walkins.json

This is probably best as it will involve very minimal changes to the schema and there likely won't be a need to ever heat a walk-in refrigerator. Maybe we even put them under Heat/Cool HVAC templates and the refrigeration templates are kinda like "cooling only" systems (much like the "heating only" systems that are already under this section).