feat(psn): add PlayStation link card and PSN import

Settings card to link and unlink with the NPSSO, shows the expiry
date. Import page gets a PSN source; blocked when the link has ended.
English and German texts.

src/pages/SettingsPage.steamToast.test.jsx

@@ -37,6 +37,7 @@ describe('SettingsPage Steam toast', () => {
             'POST /api/auth/refresh': {ok: true, status: 204, json: async () => { throw new SyntaxError('no body'); }},
             'GET /api/version': json(404, {}),
             'GET /api/follows': json(200, {following: [], followers: []}),
+            'GET /api/library/psn-account': json(200, {enabled: false, linked: false}),
         });
     });