ELECTRON: Use steamworks.js to integrate with Steamworks SDK

[catloversg]

As we discussed on Discord, this PR replaces greenworks with steamworks.js (https://github.com/ceifa/steamworks.js).

Currently, steamworks.js does not have 2 APIs that we need. I opened 2 PRs to add those APIs (ceifa/steamworks.js#157 and ceifa/steamworks.js#158). I don't know when they will be merged, so we will use my custom build in the meantime.

How to verify the binaries:

• Check my fork at https://github.com/catloversg/steamworks.js.
• Check the build logs and artifacts at https://github.com/catloversg/steamworks.js/actions/runs/10323373419.

Tested: Windows 10 and Debian 12.

Tested Steam's features:

• Cloud Sync.
• Achievements.

[d0sboots]

There's some core architectural decisions made in steamworks.js that are baffling to me; I don't see how so much of the API can be promise-free when it must be making network requests. But, I'll take that devil in exchange for something that's maintained.

I'm a bit concerned that the removal of "async" everywhere is premature.