feat(i18n): add Polish translation

app/Config/App.php

app/Language/en/Comment.php

app/Language/en/Post.php

app/Language/fr/Comment.php

app/Language/fr/Post.php

app/Language/pl/Comment.php

app/Language/pl/Common.php

app/Language/pl/Episode.php

app/Language/pl/Fediverse.php

app/Language/pl/Home.php

app/Language/pl/Page.php

app/Language/pl/Podcast.php

app/Language/pl/Post.php

modules/Admin/Language/en/Common.php

modules/Admin/Language/fr/Common.php

modules/Admin/Language/pl/Admin.php

modules/Admin/Language/pl/Breadcrumb.php

modules/Admin/Language/pl/Charts.php

modules/Admin/Language/pl/Common.php

modules/Admin/Language/pl/Contributor.php