Outdated Layers system after Squad update v7.2.0

[fantinodavide]

Description of Issue

Squad v7.2.0 introduced a new way to handle layers, factions, and units.
Each layer now has a pair of default units, but supports all the units that match the biome and alliance restrictions, creating a wide variety of combinations along as causing incompatibility with the current version of SquadJS.

Errors or Screenshots of Issue

Layer list generated before v7.2.0
Layer list generated during v7.2.1

Squad Information

• SquadJS Version: 4.0.1
• Squad Version: >7.2.0 (Current 7.2.1)

System Information

• Operating System: Not relevant
• NodeJS Version: Not relevant
• Yarn Version: Not relevant

[fantinodavide]

@werewolfboy13 I'm planning to work on this very soon, so this could be linked to the SquadJS Projects page