Restructure the native module

Consolidate all code into the src folder

native/src/include/socket.hpp

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <sys/un.h>
+#include <sys/socket.h>
+#include <string_view>
+#include <string>
+#include <vector>
+
+struct sock_cred : public ucred {
+    std::string context;
+};
+
+socklen_t setup_sockaddr(sockaddr_un *sun, const char *name);
+bool get_client_cred(int fd, sock_cred *cred);
+std::vector<int> recv_fds(int sockfd);
+int recv_fd(int sockfd);
+int send_fds(int sockfd, const int *fds, int cnt);
+int send_fd(int sockfd, int fd);
+int read_int(int fd);
+int read_int_be(int fd);
+void write_int(int fd, int val);
+void write_int_be(int fd, int val);
+std::string read_string(int fd);
+bool read_string(int fd, std::string &str);
+void write_string(int fd, std::string_view str);