This cleans up the network interface and removes a linear hashmap search
in the network interface's priority queue.

The network interface used to need to deal with both rust and C sockets,
so it stored tagged pointers for `CompatSocket` objects. Now that the
TCP socket is the only remaining C socket, and it has a rust wrapper
`LegacyTcpSocket`, C sockets aren't used in the network interface
anymore. The network interface now only stores boxed `InetSocket`
objects. This also allows us to remove tagged pointers from our C code.

The hashmap in the priority queue used by the fifo qdisc now uses custom
hash and eq implementations, which allows us to avoid a linear search
through the hashmap which used the canonical handles to identify the
same socket.

The new hash function is more expensive since it uses a real hash
function
([`DefaultHasher`](https://doc.rust-lang.org/std/collections/hash_map/struct.DefaultHasher.html)
as used by the stdlib `HashMap`), whereas the original glib code doesn't
seem to actually use a hash function:

https://docs.gtk.org/glib/type_func.HashTable.new.html

> If `hash_func` is NULL, `g_direct_hash()` is used.


https://github.com/GNOME/glib/blob/40081f9b627904c2506b6d3837334e4ce05052da/glib/ghash.c#L2483-L2487

```c
guint
g_direct_hash (gconstpointer v)
{
  return GPOINTER_TO_UINT (v);
}
```

This PR contains a lot of changes along the rust/C boundary, but
everything seems to still work so hopefully it's correct.

This may fix #3238.

**Edit:**

There doesn't seem to be much (if any) of a performance regression. The
simulation results have remained unchanged. The
[following](https://github.com/shadow/benchmark-results/blob/master/tor/2023-11-27-T03-09-35/README.md)
are from a slightly older version of this PR, but I don't expect it
would make any difference.


![run_time](https://github.com/shadow/shadow/assets/3708797/a65e571c-e0fe-42fa-997e-3279b480e52e)
![transfer_time_5242880
exit](https://github.com/shadow/shadow/assets/3708797/11f8661c-7750-4b63-8cdf-6db718b3eb2d)

![ram_simtime](https://github.com/shadow/shadow/assets/3708797/8e605dda-6a9b-4738-a5a4-19774f056af6)

**Edit 2:** One commit was split off into #3240.