NEWS: Initial changelog for Turris OS 5.0.4

I think that this changelog is simple enough and I wouldn't add there that there are security fixes for ntpd neither updated Python packages. Most of the people does not care about that and I can describe it on the forum/Reddit.

We had a discussion with @vmyslivec and we should do a promo somehow that @prohar fixed memory corruption in mwifiex driver in the kernel itself. I will prepare a short thread on our forum and we should tweet about it. Perhaps a small news on our website wouldnt be such bad at all.