scripts: TerminalBlock_Xinya: add XY308-2.54-NP screw terminals
Add script to generate footprints for http://www.xinyaelectronic.com/product/xy308-254, also fixed an import error found while running the script.
Note that some measures are not available in the CAD diagrams, I've used FreeCAD scaled images to estimate the missing values (also checking with some real connectors).
Footprints: kicad-footprints!3467 (merged)
Edited by Gerard Marull-Paretas