[System] Add power internal APIs

[System] Add power internal APIs

Allows using native power internal APIs.

These are newly added to System/Device/Power
- public static void ConfirmWaitCallback(UInt64 wait_callback_id)
	-> It informs the deviced that it is okay to take actual action to change state.
- public static void CancelWaitCallback(UInt64 wait_callback_id)
	-> It informs the deviced of that it needs to undo the current transition.
- public static int ChangeState(PowerState state, int timeout_sec)
	-> It Sends a request for changing power state asynchronously with timeout sec.
- public static int CheckRebootAllowed()
	-> It checks if reboot is possible on the current device state.
- public static PowerTransitionReason GetWakeupReason()
	-> It returns power wake up reason.
- public static PowerLockState GetLockState(PowerLock type)
	-> It returns the status of power lock(locked/unlocked).

To notify callback event, 4 types EventHandler is added.
- public static event EventHandler<PowerStateChangeRequestEventArgs> StartStateChangeRequestCallback
- public static event EventHandler<PowerStateChangeRequestEventArgs> NormalStateChangeRequestCallback
- public static event EventHandler<PowerStateChangeRequestEventArgs> SleepStateChangeRequestCallback
- public static event EventHandler<PowerStateChangeRequestEventArgs> PoweroffStateChangeRequestCallback
- public static event EventHandler<PowerStateChangeRequestEventArgs> RebootStateChangeRequestCallback
- public static event EventHandler<PowerStateChangeRequestEventArgs> ExitStateChangeRequestCallback
	-> With this eventhandler, it is possible to get event from ChangeState handling.
		For example,
		1. Add callback event to NormalStateChangeRequestCallback.
		2. Request power state change with ChangeState(PowerState.Normal, timeout_sec)
		3. After power state change request done, it returns result as invoke callback event.

- public static event EventHandler<PowerStateWaitEventArgs> StartStateWaitCallback
- public static event EventHandler<PowerStateWaitEventArgs> NormalStateWaitCallback
- public static event EventHandler<PowerStateWaitEventArgs> SleepStateWaitCallback
- public static event EventHandler<PowerStateWaitEventArgs> PoweroffStateWaitCallback
- public static event EventHandler<PowerStateWaitEventArgs> RebootStateWaitCallback
- public static event EventHandler<PowerStateWaitEventArgs> ExitStateWaitCallback
	-> As adding event callback to above eventhandler, it is possible to get event
	    when the power state changes to Specific Power state.
		For example,
		1. Add callback event to SleepStateWaitCallback.
		2. When the power state changes to Sleep state, callback event will be invoked.

- public static event EventHandler<PowerTransientStateWaitEventArgs> TransientResumingEarlyStateWaitCallback
- public static event EventHandler<PowerTransientStateWaitEventArgs> TransientResumingStateWaitCallback
- public static event EventHandler<PowerTransientStateWaitEventArgs> TransientResumingLateStateWaitCallback
- public static event EventHandler<PowerTransientStateWaitEventArgs> TransientSuspendingEarlyStateWaitCallback
- public static event EventHandler<PowerTransientStateWaitEventArgs> TransientSuspendingStateWaitCallback
- public static event EventHandler<PowerTransientStateWaitEventArgs> TransientSuspendingLateStateWaitCallback
	-> As adding event callback to above eventhandler, it is possible to get event
	    during the power transition.
		For example,
		1. Add callback event to TransientResumingLateStateWaitCallback.
		2. When the power transient state changes to ResumingLate state, callback event will be invoked.

- public static event EventHandler<PowerLockStateChangedEventArgs> CpuLockStateChangedCallback
- public static event EventHandler<PowerLockStateChangedEventArgs> DisplayNormalLockStateChangedCallback
- public static event EventHandler<PowerLockStateChangedEventArgs> DisplayDimLockStateChangedCallback
	-> As adding event callback to above eventhandler, it is possible to get event
	    when the power lock state is changed.
		For example,
		1. Add callback event to DisplayNormalLockStateChangedCallback.
		2. When the DisplayNormal power lock state is changed, callback event will be invoked.

To use new APIs, below enumeration is also added.
- public enum PowerTransitionReason
	-> It represents power transition reason
- public enum PowerState : uint
	-> It represents power state.
- public enum PowerTransientState : uint
	-> It represents power transient state.
- public enum PowerLockState
	-> It represents power lock state locked or unlocked.

Detailed example, information is added to API/EventHandler/Enumeration definition.

Signed-off-by: Yunhee Seo <yuni.seo@samsung.com>