Create RemovableDriveReaderTask
Create an interface in bramble-api, with an impl in bramble-core, for a task that reads data from a file for syncing with a given contact. It should be possible to attach and detach observers for observing the progress of the task (see #2013 (closed) and #2014 (closed)). The task should unregister itself with the RemovableDriveManager (see #2016 (closed)) when it finishes running.
Subtask of #1802 (closed)