Add missing function getSocketOption

[rtpmsys]

There is a function for setting socket options (setSocketOption) but the corresponding function to read the socket options is missing.
This PR provides the missing function getSocketOption.

Tests scenarios

Tested this on ESP32 with the following code:

WiFiClient client;
int rcvbuf_size = 0;
client.getSocketOption(SOL_SOCKET, SO_RCVBUF, &rcvbuf_size, sizeof(int));

The int rcvbuf_size will contain the receive buffer size of the socket.

This is the second part of #7361 (now closed) which was split into PR #7686 (merged) and this one

[mrengineer7777]

Oops. LWIP getsockopt(). Edit: Expected parameters may have changed.

In file included from /home/runner/Arduino/hardware/espressif/esp32/libraries/WiFi/src/WiFiClient.cpp:22:
/home/runner/Arduino/hardware/espressif/esp32/tools/sdk/esp32c3/include/lwip/lwip/src/include/lwip/sockets.h:635:81: note:   initializing argument 5 of 'int getsockopt(int, int, int, void*, socklen_t*)'
 static inline int getsockopt(int s,int level,int optname,void *opval,socklen_t *optlen)

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