Adds horizontal/vertical grids.

These are composable functions that can render fixed-size horizontal or
vertical grids of cells. They are "fixed size" as in: they don't scroll
like their "Lazy" counterparts.

Bug: 280877228
Test: tested manually using the new screen added to the Compose Gallery
app. Please see screen recording in the other CL in this topic.

Change-Id: I5effca8fd12a0c9e77efb9b3438d2e40adb789f3