feat: proxy setting (#1031)

* feat: add a proxy option into settings

* feat: add a proxy option into settings

* fix: use undici proxy agent

server/lib/settings/index.ts

@@ -119,6 +119,7 @@ export interface MainSettings {
   mediaServerType: number;
   partialRequestsEnabled: boolean;
   locale: string;
+  httpProxy: string;
 }
 
 interface PublicSettings {
@@ -325,6 +326,7 @@ class Settings {
         mediaServerType: MediaServerType.NOT_CONFIGURED,
         partialRequestsEnabled: true,
         locale: 'en',
+        httpProxy: '',
       },
       plex: {
         name: '',