Is it possible to have attachment column in a table grid?
There is no explicit attachment column, but you can actually use following approach:
attach the files to the issue
mention the file in a text column which is wiki enabled using [col.xyz.renderer|https://wiki.idalko.com/display/TGPD/col.xyz.renderer] property
Using the notation \[^attachmentname\] in the text column will provide a link to the file