make custom / self-validation fuzzy markers more elegant

triggered by this stack overflow question: https://stackoverflow.com/a/57167955/143475

today:

* def date = { month: 3 }
* def isThree = function(x){ return x == 3 }
* match date == { month: '#? isThree(_)' }

proposed:

* def date = { month: 3 }
* def isThree = function(x){ return x == 3 }
* match date == { month: '#?isThree' }

we can certainly do this with the JS - I think it’s neat 😃

[ptrthomas]

@hueller yes there is 😃 init them in karate-config.js. you can choose to name-space them like this example: https://github.com/intuit/karate/blob/master/karate-junit4/src/test/java/com/intuit/karate/junit4/config/config-dir.feature

or you can use karate.merge() to add them all to the returned config JSON after calling e.g. utils.feature

personally I don’t encourage doing too much setup in karate-config.js because large projects will need specific things for different suites, and there is a slight performance penalty since it is called for every scenario. but YMMV

[ptrthomas]

@gredler feel free to submit a PR