Added usernames with fixed domain name

app/src/main/java/eu/faircode/email/FragmentQuickSetup.java

@@ -325,9 +325,12 @@ public class FragmentQuickSetup extends FragmentBase {
                         List<String> users;
                         if (provider.user == EmailProvider.UserType.LOCAL)
                             users = Arrays.asList(username, email);
-                        else if (provider.user == EmailProvider.UserType.VALUE)
-                            users = Arrays.asList(provider.username, email, username);
-                        else
+                        else if (provider.user == EmailProvider.UserType.VALUE) {
+                            String user = provider.username;
+                            if (user.startsWith("*@"))
+                                user = username + user.substring(1);
+                            users = Arrays.asList(user, email, username);
+                        } else
                             users = Arrays.asList(email, username);
                         Log.i("User type=" + provider.user +
                                 " users=" + TextUtils.join(", ", users));

app/src/main/res/xml/providers.xml

@@ -210,7 +210,8 @@
         name="Posteo.de"
         documentation="Please check if <a href="https://posteo.de/en/help/activating-additional-email-account-protection">additional email account protection</a> isn't enabled."
         domain="posteo\\..*"
-        link="https://posteo.de/en/help/how-do-i-set-up-posteo-in-an-email-client-pop3-imap-and-smtp">
+        link="https://posteo.de/en/help/how-do-i-set-up-posteo-in-an-email-client-pop3-imap-and-smtp"
+        user="*@posteo.net">
         <imap
             host="posteo.de"
             port="993"