Translation file for polish language

Polish.lng.txt

[x] I understand that feature requests are no longer accepted except for those listed here: https://github.com/libgenapps/LibgenDesktop/issues/27

Choose one of the following:

[ ] this is a bug report;
[x] this is a new translation suggestion.

Hi, I maked translation file for polish language, based on english. I have tested it since 2 months on my locally installed application and it seems good.

PS.: I'm completly newbie on Github...

Regards G.

libgenapps / LibgenDesktop

Translation file for polish language #38