Summary

Expo users who publish an app with expo build:android will use a database file like RKStorage-scoped-experience- <encoded-project-slug> when they eject, the
database file will be RKStorage, this effectively prevents many users from being able to eject expo/expo#8220 and use this package.

This PR introduces parity for an iOS feature that migrates the database directory.

1. Check to see if RKStorage file exists (if not bail out).
2. Query all files in the database directory starting with RKStorage-scoped-experience-
3. Get the most recently modified file to migrate. This is useful because users who change their slug and republish may have multiple database files and they'll want to use the most recent one.
4. Copy the contents of this file to RKStorage
5. Delete all of the scoped database files. This creates parity with iOS.

Test Plan

Testing this feature is a little involved.

Managed -> Bare

0. Delete the app -- effectively deleting all of it's data and the RKStorage file.
1. Comment out the line AsyncStorageMigration.migrate(reactContext);
2. Change "RKStorage" to something like RKStorage-scoped-experience-foobar-1
3. Build the app, make a few modifications.
4. Repeat the last two steps with a new storage name (RKStorage-scoped-experience-foobar-2) -- This is to test that the most recent slug gets used.
5. Uncomment the line AsyncStorageMigration.migrate(reactContext); and change the database name back to RKStorage.
6. Build the app, you'll notice the logs print out info about the migration (ScopedStorageMigration log tag). The AsyncStorage in-app should have changed to match the most recent modifications from RKStorage-scoped-experience-foobar-2.
7. Reload the app, you should see no longs related to the migration.

Bare only

0. Delete the app -- effectively deleting all of it's data and the RKStorage file.
1. Build the app, you should see a log "No scoped database found" -- This is what users who run AsyncStorage for the first time without ever using Expo will see.
2. Reload the app and there should be no logs related to the migration.