Activity memory leak caused by anonymous threads

An anonymous inner class will hold a reference to the this pointer of the outer class and will not be released until the thread ends.

They will hold the Activity and prevent its timely release. Please check the Runnables and Threads below.

https://github.com/nextcloud/android/blob/master/app/src/main/java/com/owncloud/android/ui/activity/UserInfoActivity.java#L315
https://github.com/nextcloud/android/blob/master/app/src/main/java/com/owncloud/android/ui/activity/DrawerActivity.java#L1151
https://github.com/nextcloud/android/blob/master/app/src/main/java/com/owncloud/android/ui/activity/NotificationsActivity.java#L225
https://github.com/nextcloud/android/blob/master/app/src/main/java/com/owncloud/android/ui/activity/DrawerActivity.java#L822
https://github.com/nextcloud/android/blob/master/app/src/main/java/com/owncloud/android/ui/activity/PassCodeActivity.java#L414
https://github.com/nextcloud/android/blob/master/app/src/main/java/com/owncloud/android/ui/activity/ConflictsResolveActivity.java#L193
https://github.com/nextcloud/android/blob/master/app/src/main/java/com/owncloud/android/ui/activity/SettingsActivity.java#L811