Integration with mod.io ecosystem

There was a comment a while ago, that I couldn't find any more, that was proposing to integrate with mod.io for easier distribution of modpacks/assetpacks. I wanted to bring that up and put that on the table again, as I read a bit about it and find the concept quite nice:

We could make use of

• their open source C/C++ SDK within the engine (probably not needed due to our own modding API+nyan),
• a python wrapper for organising mods within the launcher or from inside other python modules,
• the rust interface for the server-side implementation (that I assume here will be written in rust, but we still didn't agree on this) or
• if we are eager to have total freedom of dependencies we could just make direct use of their REST API and implement the rest ourselves.

Here are some more details on the general implementation.

There was the idea that I kind of liked to share mods via p2p in #371. But I don't know how relevant that still is in a dedicated server setup. It could be kind of a fallback solution though if we would be eager to implement a p2p-fallback-system for multiplayer.

Update: jj was setting up openage at mod.io.

Start by reading the mod.io implementation documentation and the related p2p discussion in issue #371. Review how the engine, launcher, and dedicated-server setup currently handle mod distribution, then define whether the integration should use an SDK, wrapper, or REST API. Done means an agreed scope and implementation plan for mod.io support.