Add possibility to get terminal default foreground and background colors

[PavelTurk]

I searched through the code but couldn't find a way to retrieve the default background/foreground colors of the terminal. At the same time, for Windows, as I understand, the colors are defined -

jline3/terminal-jna/src/main/java/org/jline/terminal/impl/jna/win/WindowsAnsiWriter.java

Line 90 in 46bd37d

originalColors = info.wAttributes;

That's why I suggest to add this feature.