BUG: extra leading space in to_string when index=False
- [x] closes #24980 , xref #28538
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

I still see people posting issue for the change of behaviour in `to_string(index=False)` on pandas such as #28538 , so I think it might be worth it to reopen my previous stalled PR #25000 and see if could get it solved this time.

All the changes have been made based on the reviews in PR #25000 and for detailed summary and explanation, please check https://github.com/pandas-dev/pandas/pull/25000#issuecomment-458714951
Feel free to take a look and any review and comments are very welcomed!