LibCore: Remove Core::Socket :^)

This class is one of the last users of Core::IODevice and is no longer
used itself.

Userland/Libraries/LibCore/Socket.h

@@ -1,77 +0,0 @@
-/*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#pragma once
-
-#include <AK/Function.h>
-#include <AK/Span.h>
-#include <LibCore/IODevice.h>
-#include <LibCore/SocketAddress.h>
-
-namespace Core {
-
-class Socket : public IODevice {
-    C_OBJECT(Socket)
-public:
-    enum class Type {
-        Invalid,
-        TCP,
-        UDP,
-        Local,
-    };
-    virtual ~Socket() override;
-
-    Type type() const { return m_type; }
-
-    virtual bool connect(const String& hostname, int port);
-    bool connect(const SocketAddress&, int port);
-    bool connect(const SocketAddress&);
-
-    ByteBuffer receive(int max_size);
-    bool send(ReadonlyBytes);
-
-    bool is_connected() const { return m_connected; }
-    void set_blocking(bool blocking);
-
-    SocketAddress source_address() const { return m_source_address; }
-    int source_port() const { return m_source_port; }
-
-    SocketAddress destination_address() const { return m_destination_address; }
-    int destination_port() const { return m_destination_port; }
-
-    virtual bool close() override;
-    virtual void set_idle(bool);
-
-    Function<void()> on_connected;
-    Function<void()> on_error;
-    Function<void()> on_ready_to_read;
-
-protected:
-    Socket(Type, Object* parent);
-
-    SocketAddress m_source_address;
-    SocketAddress m_destination_address;
-    int m_source_port { -1 };
-    int m_destination_port { -1 };
-    bool m_connected { false };
-
-    virtual void did_update_fd(int) override;
-    virtual bool common_connect(const struct sockaddr*, socklen_t);
-
-private:
-    virtual bool open(OpenMode) override { VERIFY_NOT_REACHED(); }
-    void ensure_read_notifier();
-
-    Type m_type { Type::Invalid };
-    RefPtr<Notifier> m_notifier;
-    RefPtr<Notifier> m_read_notifier;
-};
-
-}
-
-template<>
-struct AK::Formatter<Core::Socket> : Formatter<Core::Object> {
-};