Create body with mixed layout

In addition to having layouts specified using rows and columns, we can have mixed layouts that combine the two.

Let's create two rows where the first row includes the following content:

# Row 1
  box(
    width = 12,
    title = "Regular Box, Row 1",
    "Star Wars, nothing but Star Wars"
    )

and a second row has two columns, where each column has the following content:

# Row 2, Column 1
  infoBox(
    width = NULL,
    title = "Regular Box, Row 2, Column 1",
    subtitle = "Gimme those Star Wars"
    )

# Row 2, Column 2
  infoBox(
    width = NULL,
    title = "Regular Box, Row 2, Column 2",
    subtitle = "Don't let them end"
    )

Create Row 1 with the box() function in the first code block above.
Create Row 2, Column 1 with width = 6 and the single infoBox() function in the second code block.
Create Row 2, Column 2 with width = 6 and the single infoBox() function in the third code block.
Rerun the shiny app with these updates.