Create a config class to manage config data

[rtnpro]

As mentioned here: #522 (comment), management of config data is becoming convoluted using a dictionary. It'd be best if we create a Config class which abstracts all operations (loading, resolving of config data) on config data and provides a clean interface to interact with the config data.

[cdrage]

Yeahhhh. 👍 for this. Let's get this implemented.

Albit this should be added post-GA as to not incur any bugs introduced before-hand.

[dustymabe]

I'd also like to make sure that this config class keeps track of where values are provided from and tracks a hierarchy. i.e. if namespace variable exists in answers.conf as well as was provided on the command line via --namespace, I'd like the class to keep track of both values as well as the priority. If the command line has higher priority then we should return that one when a calling function asks for the value of namespace.