Project deletion may fail if files are currently in use:

1. Import the attached project
2. Try to delete it as soon as possible
3. -> deletion will intermittently fail with various unhandled exceptions logged in CCS Server log, the project will remain in workspace, and it can be deleted later

This happens because many asynchronous jobs are running right after an import, to auto-migrate the project, to generate clangd database, etc. We should try catching exceptions when deleting a project, not even necessary to log them. And automatically attempt to delete it again repeatedly (with a delay between each attempt and with limited attempts). If deletion still fails after a certain number of attempts, then log the last error only, and show an error notification to user in the IDE.