Update polish variants

[marcin-serwin]

The default polish variant was based off PN-83/P-55366 that was recalled in 2014. Per PWN the version that is currently preferred is the inner-pointing guillemets, though others are allowed. This PR switches the default and alternative variants in the package and adds a fourth one described in PN-83/P-55366 for completeness sake.

After the changes the code

\documentclass{article}

\usepackage[polish]{babel}
\usepackage{csquotes}

\begin{document}
\enquote{Cytat \enquote{wewnątrz} cytatu}

\setquotestyle[guillemets*]{polish}
\enquote{Cytat \enquote{wewnątrz} cytatu}

\setquotestyle[quotes]{polish}
\enquote{Cytat \enquote{wewnątrz} cytatu}

\setquotestyle[oguillemets]{polish}
\enquote{Cytat \enquote{wewnątrz} cytatu}
\end{document}

produces