Simplify Global object and scope section

[MicFin]

The following should be removed as discussed with @jrhorn424 because it is out of scope of the lesson and adds confusion. Also, our browser-template and node-template break these expectations so it will not be useful information OTHER THAN for interviews.

this in the Global Scope Depends on the Environment

In browsers
The top-level scope is the global scope.
In the top-level scope in browsers `this` is equivalent to window.
- That means that in browsers if you're in the global scope let/const/var will define a global variable.

In Node.js
The top-level scope is not the global scope.
-In the top-level code in a Node module, `this` is equivalent to `module.exports`.
-That means if you let/const/var inside a Node.js module will be local to that module.
Node does have a global variable named global and is documented [here](https://nodejs.org/api/globals.html#globals_global).
-Since let/const/var variables are local to each module,
-global is the true global variable that is shared across modules.

-console.log("In Browser vs In Node: this is ", this);
-console.log("this === window, ", this === window);
-console.log("this === module.exports, ", this === module.exports);