Add convenience method(s) for editing system settings

[ctrevarthen]

We often want to test how different system settings (language, network, location) affect the app. Currently, the way to do this in Android seems to be to start the Settings app as a separate app during the test, make changes, then quit the settings app. This seems like something that would be a good candidate to automate.

https://forum.katalon.com/t/detect-system-language-setting-list-in-android-device/21186/2

At this point, I'm not clear if it would be something we could do on iOS.