don't set "en" as the default language, use the preferred language of the browser (#2018)

commafeed-client/src/app/types.ts

@@ -243,7 +243,7 @@ export interface SharingSettings {
 }
 
 export interface Settings {
-    language: string
+    language?: string
     readingMode: ReadingMode
     readingOrder: ReadingOrder
     showRead: boolean

commafeed-server/src/main/java/com/commafeed/frontend/model/Settings.java

@@ -18,7 +18,7 @@ import lombok.Data;
 @RegisterForReflection
 public class Settings implements Serializable {
 
-	@Schema(description = "user's preferred language, english if none", required = true)
+	@Schema(description = "user's preferred language, english if none")
 	private String language;
 
 	@Schema(description = "user reads all entries or unread entries only", required = true)

commafeed-server/src/main/java/com/commafeed/frontend/resource/UserREST.java

@@ -144,7 +144,6 @@ public class UserREST {
 			s.getSharingSettings().setBuffer(true);
 
 			s.setScrollMarks(true);
-			s.setLanguage("en");
 			s.setScrollSpeed(400);
 			s.setScrollMode(ScrollMode.IF_NEEDED);
 			s.setEntriesToKeepOnTopWhenScrolling(1);