Create $/unit to $/sqft conversions for (some) commercial baseline technologies

[trynthink]

Most end uses now have complete cost, performance, and lifetime data, including many smaller end uses for which EIA does not provide these data from AEO/NEMS. These additional data are found in the cpl_envelope_mels.json file.

For commercial buildings, the data in that JSON file for the "non-PC office equipment" and "MELs" end uses isn't pulled into the cpl_res_com_*.json input files because the cost data are reported in $/unit in cpl_envelope_mels.json, and the cost inputs are expected in $/ft². Conversions are needed to translate from $/unit to $/ft² for these end uses.