Allow us to close portions of the debugger

- [x] I'm using the latest version of react-native-debugger
- [x] I have read [README.md](https://github.com/jhen0409/react-native-debugger/blob/master/README.md)

React Native version: [0.40.0]
Platform: [Android]
Is real device of platform: [No]? (Phrasing of this is odd - I'm using an emulator atm)
Operating System: [Windows]

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There are times when I'm doing UI work and there are times when all I want is a console. Please allow us the option to close portions of the debugger. It's not very space efficient to hit the `Toggle React-Tools` and it turns off but the frame is still there and cannot be shrunk to a smaller size.


As you can see from the above screenshot it kind of takes up unnecessary space when tiling windows in specific ways