SyncUserProfileController

When the user comes online, there needs to be a controller that pushes all local User object (so Patient and Provider) changes to the elasticsearch database (if they are more recent than the versions on the database).

The main thread does not wait on this, it is an AsyncTask launched in the background that goes about the task.

see #252

Start by locating the User, Patient, and Provider models and the existing Elasticsearch integration. Determine how the controller should detect newer local versions and run the synchronization asynchronously when the user comes online; done means all newer local changes are pushed without blocking the main thread.

Written by the indexing model from the issue text.