[Feature Request] Reproducible builds

Since this will be a federated package registry, it would make sense to enforce reproducible builds. I think https://reproducible-builds.org has all the information necessary and has thought about it more deeply than I have. If I may summarize it:

- Published code should **never** be minimized and should be built by at least more than one instance
- Build tools and order **must** be pre-defined
- Reproduction anywhere (be it on the server or the dev's machine) must be possible for verification