New STS3+STS5 geometry

In this geometry version, we have introduced the gap of 2 cm between the STS3 and STS5 block. The first three stations are located at the same position as they are in the STS v21e. The Stations 4-8 are moved by 2cm to downstream side
due to gap increased between STS3 and STS5 block. The box size in the Z direction remained the same. However, there is a only change in the box size in XY direction. There is box included around the STS3 block.