Minimize a Task whenever we reach the Desktop Task limit

- Introduce DesktopTasksLimiter to limit the number of visible Desktop
Tasks
- Keep track of minimized Desktop Tasks in DesktopModeTaskRepository
- Call into DesktopTasksLimiter from DesktopTasksController whenever we
  handle a transition that might cause us to hit the task limit.
  - to minimize a Task we reorder it to the bottom of the Desktop Tasks,
    placing it behind the Home Task. We mark the task as minimized in
    DesktopModeTaskRepository later when the transition is ready.
- Add a SystemProperty 'persist.wm.debug.desktop_max_task_limit' to
  control the maximum Task limit. To update the limit to X tasks, run:
  'adb shell setprop persist.wm.debug.desktop_max_task_limit X'

Bug: 332503075, 316115519
Test: unit tests
Change-Id: Ia34b67b4628d50e99347d9680e5a869ca666eaa3