News feed aggregator from several sources

Task (`full description will be added when the program is ready :)`)

News feed aggregator from several sources (for example lenta and gazeta or newsapi with different sources)

The application must display news in one list, sorted by publication date, from two or more sources
Applications must be scalable to add new sources
The application must indicate its source in the news
A count of the number of transitions to the news should be implemented.
A count of the number of transitions to the news should be implemented.
Adding selected news should be implemented.
Update by timer (period selection in settings).
Settings (for example: update frequency, enable/disable news source), saved on restart.
Using a database to store news
Thoughtful and scalable project structure
Test coverage