small passphrasedialog update #1206

• change dialog title to "Passphrase Dialog as that's better for distinction on Transifex
• remove style-sheet for bold font and use default Qt Designer option for bold
• remove capsLabel default text -> results in removal of a clear() in the source

I tried to move the string, which is displayed when Caps Lock is active into the .ui file and use setVisible(true / false), but that resulted in layout jumping / small layout movements, which were rather ugly!

You're changing the constant MAX_PASSPHRASE_SIZE into a literal 1024. Better to leave it as before, IMO, so MAX_PASSPHRASE_SIZE can be updated easily.

@laanwj Do you agree with luke-jr on his suggestion? What about the other changes? I'm interested in a small integration of these little commits :).

I agree with luke-jr here. Please don't try to fix things that are not broken :/ Constants are always better than magic values, even in the XML file.

Focus on the things that this pull request fixes/improves, which is not clear to me.

Updated to do only minor changes, I think style-sheets should be avoided if there is a Qt Designer default option for that goal. And the removal of the capsLabel default text results in one string less to translate that is never used anyway and as result allows to remove a clear() in the code.