Get rid of netconf-tcp project

Get rid of netconf-tcp project

netconf-tcp includes basic TCP server implementation used in netconf
project. It also contains instantiation logic for tcp server used by
css netconf northbound.

css is no longer in the game. Remove TCP server instantiation logic for
css netconf northbound endpoint. Move NetconfNorthboundTcpServer class
(only class used elsewhere) to mdsal-netconf-tcp projects. This project
is its primary and only user now.

Change-Id: I7dea91f33f3c3f6364d57e5a590505a058fd7957
Signed-off-by: Jakub Morvay <jmorvay@frinx.io>