test(pageObjects): Added rxEnvironment Page Object

Added a page object for rxEnvironment. getEnv returns the current environment.
I've thought about it, and the example you've posted in your link is for typed languages.

I felt it was ok to use it here, seeing how the "typical" use case is covered by the `undefined` input. This requires the user to pass in something specifically to deal with an edge case. From there, it'd be up to them to properly highlight their intentions by naming the true flag to something meaningful.