Add MAGIC Telescope detector class

[astrojarred]

Description
The MAGIC Telescopes are a pair of 17m gamma-ray telescopes on the island of La Palma, Spain. Given the similarities of ML tasks between gamma-ray and neutrino experiments (event classification and arrival direction / energy regression), GraphNeT models have already been successfully used for gamma-ray event reconstruction [eg ICRC 2025].

This preliminary issue is a small one: add the MAGIC telescopes detector class. A further issue would add the MAGIC reader class.

Requirements

• Make sure the format of the MAGIC detector class matches what's expected from a new experiment.