Add .STP/.STEP file capability to CAD widget

Specifically Step 242 files are robust CAD files that include manufacturing details, notes, and instructions. Adding the functionality to manipulate these files within the CAD widget would benefit customers that use these advanced CAD files (e.g. contract manufacturers, made-to-order job shops, machine shops). These would also be a more dynamic solution for customers with drawing details that are subject to change and/or have rigid release processes. Updating the drawings with the latest version would pull in all the notes native to the .STEP file without the need to update Tulip text boxes on each app step.

More info on Step 242 files

Thanks @scottmattocks, we agree - STEP is a common type that we plan on supporting at some point in the future. Also, if you have more examples on how CAD files are being used, please send them along!