chore(cbindings): Adding cpp example that integrates the 'libwaku' (#2079)

* Adding cpp example that integrates the `libwaku`

---------

Co-authored-by: NagyZoltanPeter <113987313+NagyZoltanPeter@users.noreply.github.com>

examples/cpp/base64.cpp

@@ -0,0 +1,53 @@
+
+#include <vector>
+#include "base64.h"
+
+// Base64 encoding
+// source: https://nachtimwald.com/2017/11/18/base64-encode-and-decode-in-c/
+size_t b64_encoded_size(size_t inlen)
+{
+	size_t ret;
+
+	ret = inlen;
+	if (inlen % 3 != 0)
+		ret += 3 - (inlen % 3);
+	ret /= 3;
+	ret *= 4;
+
+	return ret;
+}
+
+const char b64chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+void b64_encode(char* in, size_t len, std::vector<char>& out)
+{
+	size_t  elen;
+	size_t  i;
+	size_t  j;
+	size_t  v;
+
+	if (in == NULL || len == 0)
+		return;
+
+	elen = b64_encoded_size(len);
+	out.reserve(elen+1);
+
+	for (i=0, j=0; i<len; i+=3, j+=4) {
+		v = in[i];
+		v = i+1 < len ? v << 8 | in[i+1] : v << 8;
+		v = i+2 < len ? v << 8 | in[i+2] : v << 8;
+
+		out[j]   = b64chars[(v >> 18) & 0x3F];
+		out[j+1] = b64chars[(v >> 12) & 0x3F];
+		if (i+1 < len) {
+			out[j+2] = b64chars[(v >> 6) & 0x3F];
+		} else {
+			out[j+2] = '=';
+		}
+		if (i+2 < len) {
+			out[j+3] = b64chars[v & 0x3F];
+		} else {
+			out[j+3] = '=';
+		}
+	}
+}