Good evening, I have been working on a new small feature which aims to validate if a value is present in a configuration through a first match validation.
This is useful when looking for specific values in multiple configurations and often can be leveraged to return the right Configuration if a value is present. It can also be used to validate the integrity of a Configuration. It is natively present in *java.util.Properties* (see JavaDoc <https://docs.oracle.com/javase/8/docs/api/java/util/Hashtable.html#containsValue-java.lang.Object-> ). I would like to ask if you find this worthy of being added to *commons.configuration2* and I would like to ask if it is ok if I submit a PR with this implementation? *My fork: * https://github.com/rikkarth/commons-configuration/tree/feat/configuration-contains-value Worth noting that this is my first implementation and I haven't written any JavaDoc or cleaned up (too much at least). I've made some tests which are passing (not on GitHub apparently). I would appreciate any feedback in regards to this implementation. Thank you for your time and consideration. Best Regards Ricardo Mendes
