Revise a need of JsonPathFinder and groom the API in general.

[besok]

JsonPathFinder seems to be redundant. Probably, better to revise the API a remove it

[xMAC94x]

@besok 3 potential API changes would also be:

• get rid of JsonPathInst, just export the JsonPath (in case it changes in the future, we use semver anyways)
• change jsonpath_rust::JsonPathQuery interface to use a JsonPath rather than a &str, but at the same time implement the From<&str> trait for JsonPath, so that json.path("$..book[?(@.author size 10)].title".into()) works
• we have JsonPathValue and JsonPtr, maybe we only need one and have Option<JsonPtr> for the None case

[xMAC94x]

I can have a look into these points after #58 got merged. Not a huge fan of gigantic refactoring PRs, rather do it in smaller steps. What do you think ?

[xMAC94x]

@besok any comment at this ? maybe any way to make communication easier than via github ? Like discord ?

[besok]

Hey! Sorry, I am on vacation and very slowly respond. Yeah, sure. You can take it and split it into a smaller prs. I will finish the review of the current pr this week.