The name `harePackages` may give thet impression that programs written in
Hare should be added to its scope, which is not true: its purpose is to
encapsulate Hare third party libraries.
Thus, changing it to `hareThirdParty` makes it clear what its purpose
is --- just like renaming `hare-packages.nix` to `hare-third-party.nix`
on `pkgs/top-level`.
Moreover, remove the `hare` and `harec` packages from the newly renamed
`hareThirdParty` scope, since they are not Hare libraries.
Finally, remove the inheritance of `harePackages.hare` on `himitsu` and
`himitsu-firefox`, the two programs using `hare` on nixpkgs: both `hare`
and `harec` are directly accessible since 12449072[1], when they were
moved from `aliases.nix` to `all-packages.nix`, with the difference now
that they do not belong anymore to `harePackages` --- now `hareThirdParty`.
[1]: 1244907222
