To add the Android.bp of ExternalStorageProvider

ExternalStorageProvider doesn't have any tests yet.
1. Convert Android.mk to Android.bp
2. Add init testcase
3. formatted by bpfmt -s -w Android.bp

Fixes: 117812397
Test: atest ExternalStorageProviderTests

Change-Id: I74235832f453110742de0b15cb14fac7514ecf0e
6 files changed