Feedback when scan for devices ended

[guyluz11]

Currently (in the new version that is not on the store) there is no way to know when a scan for devices is done.

We can implement it in a couple of options but the easiest and quick option is to show fluttertoast on complete saying something like "Done" or "Scan complete".

[git-elliot]

I want scans to persist and show it as a report and previous scans also. I'll add this functionality now. Everything will be stored locally only in a database

[guyluz11]

Cool, so for local db lets use isar

[git-elliot]

I think this can be implemented using notifications because the scan process is asynchronous. I will implement this using local notifications.