make JsonPath non-private

[palatam]

Currently the JsonPath class only has a single private Constructor and the field "path" is also private.

Making both elements protected allows users to extend/override the class and its behaviour.

Currently I need to build a local version so I can make JsonPath#read returns a map of absolutePath->value (currently it only returns only the values or the absolute paths of the hits and I would need to run the #read method twice with different configs).

If this idea will be rejected I will open a new one with a discussion about a proper implementation of a feature which returns map of hits containing absolutePath->value hoping that it will get approved (after the implementation details are clear I can make a PR).