Adding alarms and reminders activity

Adding a settings screen to control the permission SCHEDULE_EXACT_ALARM.
Apps can start this by starting a newly introduced API intent
REQUEST_SCHEDULE_EXACT_ALARM.

Test: make -j RunSettingsRoboTests
Manually by UI inspection:
Settings -> Apps -> Special App access -> Alarms and Reminders
or by running:
adb shell am start -a android.settings.REQUEST_SCHEDULE_EXACT_ALARM

Bug: 171306433
Bug: 171305516
Change-Id: I1293d38fc50a22b2af46f80ab24f676ed632f964