Add RFC6901 json pointer support

Author: leonchen83

src/main/java/redis/clients/jedis/json/JsonPointer.java

@@ -5,9 +5,9 @@
 /**
  * an RFC6901 implementation that convert json pointer path to json path.
  */
-public class JsonPointer {
+class JsonPointer {
 
-  public static String parse(String path, String rootPath) {
+  static String parse(String path, String rootPath) {
     Objects.requireNonNull(path, "Json Pointer Path cannot be null.");
 
     if (path.isEmpty()) {