Rename existing tcp sink to socket sink

This renames the existing tcp sink to socket

The tcp sink has been renamed to socket. This is part of an overall effort to simplify our sinks in a manner where they can easily be “wrapped” as the foundation for upcoming sinks.

Upgrade Guide 

 [sources.my_tcp_sink]
-  type = "tcp"
+  type = "socket"
   address = "92.12.333.224:5000"
+  mode = "tcp"