Implement wasi_addr_resolve function (#1319)

Implement wasi_addr_resolve function.
    
Also slightly modify the interface to make it more accessible for the end user:
- replace port argument with the service - so the user can actually get the port for a given service if unknown
- introduce __wasi_addr_info_t and use it as a buffer for addresses, instead of generic buffer
- introduce __wasi_addr_info_hints_t so user can enable filtering on the syscall level (and therefore use smaller buffers for addresses)
- add max_size parameter for the API as an output - in case the number of addresses is bigger than the buffer size, user can repeat the call with bigger buffer

This change is very minimalistic, and it doesn't include the followings:
 1. implementation of getaddrinfo in the lib-socket
 2. sample application
Which are to be added in the following change #1336

core/shared/platform/linux-sgx/sgx_socket.c

@@ -4,6 +4,7 @@
  */
 
 #include "platform_api_vmcore.h"
+#include "platform_api_extension.h"
 
 #ifndef SGX_DISABLE_WASI
 
@@ -620,4 +621,15 @@ os_socket_shutdown(bh_socket_t socket)
     return shutdown(socket, O_RDWR);
 }
 
+int
+os_socket_addr_resolve(const char *host, const char *service,
+                       uint8_t *hint_is_tcp, uint8_t *hint_is_ipv4,
+                       bh_addr_info_t *addr_info, size_t addr_info_size,
+                       size_t *max_info_size)
+{
+    errno = ENOSYS;
+
+    return BHT_ERROR;
+}
+
 #endif