Power: add support for devices without display idle signals

Power: add support for devices without display idle signals

To workaround b/141025174, adding support for devices without display
idle signals. Also added a property to override idle display function.

Besides the idle signal support, this CL also makes touch boost duration
tunable through several new vendor properties. It also named display
idle monitor thread and cleans out the obsolete HIDL Power HAL
implementation.

Bug: 168080943
Bug: 169065024
Bug: 171494137
Test: Boot and trace
Change-Id: I76067d10958654d539624ec4cac8f346103e67bc