CMAP Freight Model v0.3 revised firm synthesis

Working development version of CMAP freight model

Main changes in this release

• Completed updates to firm synthesis for consistency with the CSVM implementation of the firm synthesis. Results for the CMAP model region are identical between the two implementations.
• Code and model structure for model are modified to match with the CSVM, and R version and packages are the same (with at this point one additional package used, "fst".
• Outputs from firm synthesis are written to .fst files (for faster IO), which will also be used through the supply chain model.
• Base year control data for the firm synthesis are from the 2019 CMAP employment data for the CMAP model region (same as used in the CSVM base year) and from 2019 QCEW data from BLS for the rest of the country. (some further calibration adjustments to the IO and foreign trade data may be necessary to fully represent a 2019 base year)

Other Notes:

• Runs in R 4.1.2
• Uses current release of rFreight, v0.1-35 (updated from v0.1.34 in CSVM to include some additional NAICS correspondences but otherwise identical)
• works through firm synthesis (later code steps included in the release are not updated at this point)