Consider that a point is defined by its coordinates and that a rectangle
is defined by the points of the upper left and lower right corners.
- Define two structures named, `point` and `rectangle`.
- The struct `point` has to have two variables, `x` and `y`, type `int`.
- The struct `rectangle` has to have two variables, `upLeft` and `downRight` type `point`.
- Our main task is to make a program that:
- Given a slice of points of size `n` returns the smallest rectangle that contains all the points in the vector of points. The name of that function is `defineRectangle`
- And calculates and prints the area of that rectangle you define.