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.test.jsx

@@ -34,6 +34,7 @@ const authRoutes = (me) => ({
     'PUT /api/users/settings/owner-lists': noBody,
     'GET /api/version': json(404, {}),
     'GET /api/follows': json(200, {following: [], followers: []}),
+    'GET /api/library/psn-account': json(200, {enabled: false, linked: false}),
 });
 
 function renderPage(me) {
@@ -294,6 +295,7 @@ describe('SettingsPage session', () => {
             'POST /api/auth/refresh': json(401, {}),
             'GET /api/version': json(404, {}),
             'GET /api/follows': json(200, {following: [], followers: []}),
+            'GET /api/library/psn-account': json(200, {enabled: false, linked: false}),
         });
         const {router} = renderWithProviders(<SettingsPage/>, {path: '/settings', entries: ['/settings'],
             guarded: true, routes: {'/login': <p>login</p>}});