Android 11 storage management v1.8.37

The requestExternalStorage:"true" flag needed to be in the AndroidManifest file, because react-native-document-picker did some bugs if that were not there. Android 11 ignores this flag, and needed to delete it. Fortunately, react-native-document-picker fixed this bug, and updating its version fixed the problem, so this flag is does not needed anymore.

Added a description dialogue to the background location permission request, to be allowed by google play.

These issues are relevant in this MR: #176 (closed) #170 (closed)