Remember the project default tab for 30 days

Created by: hiroponz

1. What does this MR do?

Remember the project default tab (Activity or Readme) for 30 days.

2. Are there points in the code the reviewer needs to double check?

No there are.

3. Why was this MR needed?

It is incommodious that the project default tab is forgotten in every new sessions(new tabs and new windows).

4. What are the relevant issue numbers / Feature requests?

Nothing.

5. Screenshots (if relevant)

Nothing.