Sturdy Dual carriage J head Bowden with 40mm Fan mount

The addition of up to 2x 40mm fans to help too keep the peek blocks on the J-head nice and cool without making the carriage soft and have failed prints.
The Extra shroud will have to keep the cool air off the prints to stop warping, especially with ABS.
Currently upgrading my printer and unable to test this part but WIP for the moment.