Add keep clear area avoidance algorithm for PiP

The algorithm computes a new position for PiP based on the registered
keep clear areas within the system. If no occlusion happens the original
position is being returned. Otherwise, the bounds are moved in one of the
available directions so that none of the keep clear areas are occluded
while keeping PiP within the display bounds.

Test: atest PipKeepClearAlgorithmTest
Bug: 183746978
Change-Id: Ic2d11861329a46e2da0448f90283f67f6e7125d7