feat(plex): selective user import (#2188)

* feat(api): allow importing of only selected Plex users

* feat(frontend): modal for importing Plex users

* feat: add alert if 'Enable New Plex Sign-In' setting is enabled

* refactor: fetch all existing Plex users in a single DB query

Co-authored-by: Ryan Cohen <ryan@sct.dev>

server/lib/settings.ts

@@ -113,6 +113,7 @@ interface FullPublicSettings extends PublicSettings {
   enablePushRegistration: boolean;
   locale: string;
   emailEnabled: boolean;
+  newPlexLogin: boolean;
 }
 
 export interface NotificationAgentConfig {
@@ -469,6 +470,7 @@ class Settings {
       enablePushRegistration: this.data.notifications.agents.webpush.enabled,
       locale: this.data.main.locale,
       emailEnabled: this.data.notifications.agents.email.enabled,
+      newPlexLogin: this.data.main.newPlexLogin,
     };
   }