Adding octagon aperture
Adding octagon aperture that could be used for Run 4 studies.
Based on fig. 3 from https://www.cockcroft.ac.uk/events/HL-LHC_UK/Documents/M1.2%20hilumi_scatter.pdf (page 3).
- A1 ... half-width of the big rectangle along X-axis
- A2 ... half-height of the big rectangle along Y-axis
- A3, A4 ... angles between X-axis and corners of the octagon in radians
Edited by Petr Balek