Add Polish translation

[Atrate]

Changes:

• Added Polish translation
• Capitalized "Firebird" where appropriate

Signed-off-by: Atrate Atrate@protonmail.com

[Vogtinator]

Thanks! Please run lrelease i18n/pl_PL.ts and add i18n/pl_PL.qm to resources.qrc.

Or if you'd like to do some cleanup, try CONFIG += lrelease embed_translations in firebird.pro, which might need some adjustments elsewhere.

[Atrate]

Done, @Vogtinator

[Vogtinator]

Looks like you did both now - with the added CONFIG values the .qm files can be dropped from the repo and resources.qrc.
If that works (you might have to adjust the path in main.cpp and mainwindow.cpp), you can do that.
Or undo the CONFIG change, as otherwise it looks good now.

[Atrate]

Alright, it's simpler to just remove the config override. Done.

[Vogtinator]

I gave it a quick try and noticed that the dock window titles aren't translated. That's most likely a bug in the code though and not related to this translation, as the other languages are also affected.

Thanks for the contribution!