Add bom.csv part number column name management

[GrandFatherADI]

JLCPCB expects to find manufacturer part numbers in a "Comment" column in bom.csv files (https://jlcpcb.com/help/article/bill-of-materials-for-pcb-assembly). Fabrication Toolkit previously used a "LCSC Part #" column for this purpose.

This update allows either a "Comment" or a "LCSC Part #" column to be used for manufacturer part numbers in the bom.csv.

[BenRoe]

That's not true. The comment column is for component values.

[GrandFatherADI]

@BenRoe that table is from JLC's web site and is on the page I linked above. It is not at all clear from the commentary on that page how the various fields in the BOM are used in the fabrication process. My experience was that putting the MPN in the comment column gave much better results for part selection.

Note that the patch doesn't force new behavior. For my use I could achieve 100% correct part matching with JLC's system using the option compared to 80% failure with the default setting.