[BUG]: Fail to fetch feed if URL field contains a paragraph break

[sakkamade]

Brief description of the issue.

If the URL field in "Add new feed" modal window contains paragraph break the feed fails to fetch.

With preceding paragraph break: Network error: protocol error.
With subsequent paragraph break: Network error: content not found.

How to reproduce the bug?

1. Add the link of the feed into URL field of "Add new feed" window
2. Tap Enter there
3. Click "Fetch it now"
4. Observe error

What was the expected result?

The paragraph breaks to be automatically stripped.

What actually happened?

The error ❤️

Other information

• OS: Arch Linux, KDE
• RSS Guard
  Version: 4.0.0 (built on Linux/x86_64)
  Revision: ddf12dd
  Build date: 30/06/2021 07:02
  Qt: 5.15.2 (compiled against 5.15.2)

[martinrotter]

I will sanitize every URLs passed to RSS Guard's network subsystem.

[martinrotter]

done - b0a1128 - should work application-wide