New STS geometries

v21a has stations with extended pitch, uses the old beam pipe, repositions the FEB boxes, and changes the material(Airex) for foam in sts wall. v21b has stations with the extended pitch, repositioned central ladders according to 40 mm diameter beam pipe and new material(Airex) for foam in STS wall. v21c has stations with extended pitch, repositioned central ladders according to 55 mm diameter beam pipe and new matrial(Airex) for foam in STS wall foam v21d has stations with extended pitch, reposition of central ladders due to provision for a 40 mm diameter beam pipe. The back side wall has a honeycomb structure Airex matrial used