Introduce BubbleBarLocation to define bubble bar location

BubbleBarLocation allows bubble bar to be positioned at the default location.
This is on the right side for LTR languages and on the left for RTL.
In addition it includes values for left and right. This allows overriding
of the default position. And pin the bar to either side.
The bar does not animate between the two states. And will immediately show
on the other side when an update is received.

Bug: 313661121
Flag: ACONFIG com.android.wm.shell.enable_bubble_bar DEVELOPMENT
Test: atest WMShellUnitTests
Change-Id: I498b20d5e7fac1d5aacdcff6a903864d6bb57ffa