Store error messages received from server to display later

[davivel]

Currently, when an operation ends with an error and the app has no specific error message for it, the error message returned from he server is used instead.

This works nice enough when the error happens while the app is open, but doesn't work fine for operations that frequently end when the user is not watching the app, such as downloads and, specially, uploads.

Storing the error messages in the local database will allow using them when the user opens the app again. Right now the only place to show those messages immediately is 'Uploads' view, as the result of failed uploads. Let's start there.

[shashvat-kedia]

@jesmrec I would like to work on this.

[jesmrec]

go for it