Add RFC6901 json pointer support

[leonchen83]

Now Path can convert RFC6901 style path to json path for example Path.ofJosnPointer("/abc/0") can convert to Path.of(".[\"abc\"].[0]")

the limitation of JsonPointer path is /abc/0 always convert to .[\"abc\"].[0] and not .[\"abc\"].[\"0\"] if users want to use .abc.0, they should use Path.of(".abc.0") instead of Path.ofJosnPointer("/abc/0")