Contractors VR mod kit is out now. TLDR, allows you to make custom maps, gamemodes, and loadouts (gun selection). 
Install guide: https://contractors.mod.io/guides/how-to-install-contractors-vr-mod-kit
Map mod guide: https://contractors.mod.io/guides/how-to-make-a-map-mod

Guides for gamemodes and loadouts coming soon apparently, and the game will get a beta in the coming days allowing mods.