Option to pull obb data with apk

[DanTheMan827]

Related to #252.

The ability to pull the obb data if any exists for an app along with the app itself would be convenient.

An app “backup” zip archive with the apk and the obb folder alongside it with maybe a manifest.

A potential structure for the archive could be as simple as:

com.myapp.apk
com.myapp/*
manifest.json

Manifest would be a mapping of archive paths to destination device paths and perhaps extra data.

On “restore”, the apk would be installed, then the files restored.

But Android can be difficult some times, so depending on the device, the app may need to be started for it to create the folder with proper permissions before restore.