Moving all configuration related file into 1 package

This looks big but it's slowly building on these 2 pull requests

https://github.com/SeleniumHQ/selenium/pull/152
and
https://github.com/SeleniumHQ/selenium/pull/153

This is step 2 in over all rebuilding of how configuration is read. In this step i'm moving all configuration files into a single package, and extracting how the parameters from yaml, json, and command line are parsed into a separate class. The configuration object does not need to know how the params are parsed etc..