feat: support {Free|Net|Open}BSD (#2311)

Adds support for `iroh`  on `NetBSD`, `FreeBSD` and `OpenBSD`.

## Status

- NetBsd
  - [x] Compiles
  - [ ] Tests passing
- [ ] Iroh: mostly passing, failures are only due to
shellrow/netdev#69
    - [x] Quinn
  - [x] Implementation adapted
- FreeBsd
  - [x] Compiles
  - [ ] Tests passing
- [ ] Iroh: mostly passing, failures are only due to
shellrow/netdev#69
    - [x] Quinn
  - [x] Implementation adapted
- OpenBsd
  - [x] Compiles
  - [ ] Tests passing
- [ ] Iroh: mostly passing, failures are only due to
shellrow/netdev#69
    - [x] Quinn
  - [x] Implementation adapted


## Caveats

- Build only in CI for now

## Related Issues

- shellrow/netdev#69
- n0-computer/quinn#9

## References

-
https://github.com/freebsd/freebsd-ports/blob/78ad38f04f51/games/jumpy/files/patch-iroh
- rust-lang/libc#3711

Closes #2306

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Co-authored-by: Floris Bruynooghe <[email protected]>