This makes it so that "on_connected" always gets called first.
Since accepted sockets are connected before construction, they have
to manually set CSocket::m_connected.
The C_OBJECT macro now also inserts a static construct(...) helper into
the class. Now we can make the constructor(s) private and instead call:
auto socket = CTCPSocket::construct(arguments);
construct() returns an ObjectPtr<T>, which we'll later switch to being
a NonnullRefPtr<T>, once everything else in in place for ref-counting.
We're going to be using dedicated server socket classes instead.
This was only implemented for CLocalSocket, and clients have been switched
over to using CLocalServer.
