Update Toast visuals + motion

Puts Toast style/animation changes behind a FeatureFlag

Toasts can be added via Toast APIs OR legacy apps can add the
window directly. Because toast windows can be added directly by legacy
apps, DisplayPolicy.java requires that toast windows are removed
after TOAST_WINDOW_TIMEOUT.  This also means Toast windows added via
the Toast APIs are subject to this timeout. Therefore, this CL also
increases the timeout by 600ms to account for SystemUI's in/out
toast animations.

Bug: 169587378
Test: atest ToastUITest
Test: manual, rotate device while toast is showing
Change-Id: Ib17655c253f4ec4f7018cc5f7939b88a50ea5014
Merged-In: Ib17655c253f4ec4f7018cc5f7939b88a50ea5014