Makes base.nix less Wayland-centric. This means:
- Don't specify support in the meta.description (since even regular Wine supports it, it's specified everywhere)
- `x11Support` and `waylandSupport` are now set in `wine-packages.nix`, like every other flag (they are also now disabled on minimal)
- Disable Darwin in supported platforms if an incompatible supportFlag is true (not just `waylandSupport`)
- Add wineRelease name for every release other than "stable" or "unstable", instead of just "wayland"
- This also fixes an inconsistency on wine-staging, where "-staging" was written after the version