The DataImportController#create action redirects back to /read path unconditionally. The only thing that's different if an error happens is that a DataImport instance is created for the current user with status "ERROR".

This ensures that the user is not left looking at a blank page (with status HTTP500, which would not be obvious to the user) if an error happens server-side when processing the POST from the "import subscriptions" form.
Moved all partials related with the data import process to the app/views/read folder, except the ones directly rendered by DataImportsController actions.

This makes more sense because these partials will only be visible in the read view anyway.
WIP: adapt the "import subscriptions" functionality to angularjs.