supplicant/esp_wifi: move supplicant to idf

Move supplicant to idf and do following refactoring:
1. Make the folder structure consitent with supplicant upstream
2. Remove duplicated header files and minimize the public header files
3. Refactor for WiFi/supplicant interfaces

components/wpa_supplicant/src/utils/base64.h

@@ -0,0 +1,23 @@
+/*
+ * Base64 encoding/decoding (RFC1341)
+ * Copyright (c) 2005, Jouni Malinen <j@w1.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Alternatively, this software may be distributed under the terms of BSD
+ * license.
+ *
+ * See README and COPYING for more details.
+ */
+
+#ifndef BASE64_H
+#define BASE64_H
+
+unsigned char * base64_encode(const unsigned char *src, size_t len,
+			      size_t *out_len);
+unsigned char * base64_decode(const unsigned char *src, size_t len,
+			      size_t *out_len);
+
+#endif /* BASE64_H */