Change socket function signatures to use os_sockaddr

* Consolidated and cleaned up some (duplicate) functions.
* Removed some unused functions that did not make sense to keep around.

Signed-off-by: Jeroen Koekkoek <jeroen@koekkoek.nl>

src/core/ddsi/CMakeLists.txt

@@ -10,6 +10,7 @@
 # SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 #
 PREPEND(srcs_ddsi "${CMAKE_CURRENT_LIST_DIR}/src"
+    ddsi_eth.c
     ddsi_ser.c
     ddsi_ssl.c
     ddsi_tcp.c