Bug report handler app via Bug Report Shortcut

- Send intent (android.internal.intent.action.BUGREPORT_REQUESTED) to bug report handler app after pressing Bug Report Shortcut
- Add config "config_bugReportHandlerEnabled" to enable this feature
- Add config "config_defaultBugReportHandlerApp" to get the package of default bugreport handler app
- Add settings CUSTOM_BUGREPORT_HANDLER_APP to get the package of custom bugreport handler app
- Add settings CUSTOM_BUGREPORT_HANDLER_USER to get the user id of custom bugreport handler app

BUG:142921485
Test: After pressing Bug Report Shortcut in manual local test:
- the intent can be sent to bugreport handler app.
- the intent can be sent to Shell if the chosen and the default bugreport handler app can't handle it.
- the intent can be sent to system user profile's default bugreport handler app if the custom profile(like work profile) is removed.
Change-Id: Idc33b47f0cc65b90cbf648bda54a1d900fef007a