Triclinic boxes megathread

MAICoS support for triclinic boxes is currently nonexisting.

Known issues:

• COM calculation across PBCs (center_cluster) does not work in triclinic boxes
• Due to the different box definitions in MDAnalysis and MAICoS, the box center of the triclinic box and the orthorombic projection is not the same, leading to artifacts because of the way MAICoS uses the box center as reference.

Hotfix: Throw error when triclinic boxes are used.