Replace logging trough pexpect with realtime logging

Problem with logging trough pexpect is that we log output only when we
expect it. That is when we access it trough pexpect. This means that
time and synchronization when logs arrive from multiple sources can't be
archived and only one source logs at the time (the one that is used
currently by pexpect). This is not ideal as we are interested in
situation such as restarting network interfaces that produce some logs
not only on router but also in container at the same time.
Synchronization on time bases in such cases is important and we can't
wait for code to call pexpect to print it to logs later on.

This instead utilizes sockets and by reading source immediately and just
passing it to socket.