whitelist background applications using ADAL library from battery optimization

[tonyquan68]

currently Microsoft applications that do background synchronization (Outlook in particular) may stop being able to sync in background, because Android does "battery optimization" on these apps. For example, the Microsoft documentation https://docs.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/outlook-for-ios-and-android/outlook-for-ios-and-android-faq mentions that for Microsoft Outlook, MIcrosoft Authenticator and the Intune Company Portal users may have to manually turn off Android's Battery Optimization for these apps in order for background sync of Microsoft apps to continue working properly. Would like to request that apps using ADAL and which run in background be able to ask the user to override "Battery optimization" using the methods described here: https://developer.android.com/training/monitoring-device-state/doze-standby#support_for_other_use_cases ideally with an explanation that this override is needed to ensure background sync continues to function.

[iambmelt]

Feature request, assigning @hamiltonha