esp_netif: Introduction of esp-netif component as a replacement of tcpip_adpter

- provides object oriented access to network intefaces
- not limited to default netifs
- more generic abstraction to network input output functions
- event handler registration removed from component responsibility
- backward compatibility layer for legacy tcpip_apapter APIs

Closes IDF-39

components/lwip/CMakeLists.txt

@@ -89,7 +89,6 @@ set(srcs
     "port/esp32/debug/lwip_debug.c"
     "port/esp32/freertos/sys_arch.c"
     "port/esp32/netif/dhcp_state.c"
-    "port/esp32/netif/nettestif.c"
     "port/esp32/netif/wlanif.c")
 
 if(CONFIG_LWIP_PPP_SUPPORT)
@@ -134,7 +133,7 @@ idf_component_register(SRCS "${srcs}"
                     INCLUDE_DIRS "${include_dirs}"
                     LDFRAGMENTS linker.lf
                     REQUIRES vfs esp_wifi
-                    PRIV_REQUIRES esp_eth tcpip_adapter nvs_flash)
+                    PRIV_REQUIRES esp_eth esp_netif tcpip_adapter nvs_flash)
 
 # lots of LWIP source files evaluate macros that check address of stack variables
 target_compile_options(${COMPONENT_LIB} PRIVATE -Wno-address)