Allow to specify the focus order of default focus and previous focus per FocusArea

Previously the focus order of default focus and previous focus is
controlled by boolean resource and can be set by the OEM for the
entire system. Now we have decided that it should be set by app
developers for each FocusArea.

Fixes: 175898378
Test: atest FocusAreaTest
Change-Id: I19e7e619f81cbe0dc9ca5187c2d2f271b15231bd
4 files changed