Add styled DoNotKillMeFragment

...va/org/briarproject/android/dontkillmelib/PowerUtils.java

...ilbox/android/dontkillme/AbstractDoNotKillMeFragment.java

...project/mailbox/android/dontkillme/DoNotKillMeFragment.kt

...org/briarproject/mailbox/android/dontkillme/DozeView.java

...oject/mailbox/android/dontkillme/HuaweiAppLaunchView.java

...t/mailbox/android/dontkillme/HuaweiProtectedAppsView.java

...rg/briarproject/mailbox/android/dontkillme/PowerView.java

...g/briarproject/mailbox/android/dontkillme/XiaomiView.java

...-android/src/main/res/drawable/ic_battery_alert_white.xml

mailbox-android/src/main/res/drawable/ic_check_white.xml

...x-android/src/main/res/drawable/ic_help_outline_white.xml

mailbox-android/src/main/res/drawable/ic_permissions.xml

...droid/src/main/res/drawable/ic_restore_mirrored_white.xml

...ox-android/src/main/res/layout/fragment_dont_kill_me2.xml

mailbox-android/src/main/res/layout/power_view2.xml

mailbox-android/src/main/res/navigation/nav_main.xml

mailbox-android/src/main/res/values/colors.xml

mailbox-android/src/main/res/values/styles.xml