Reworked image handling, added banner for profiles. Made functions to start on xivauth. Refactored some code.

LightlessSyncServer/LightlessSyncShared/Models/GroupProfile.cs

@@ -15,6 +15,7 @@ public class GroupProfile
     public string Description { get; set; }
     public int[] Tags { get; set; }
     public string Base64GroupProfileImage { get; set; }
+    public string Base64GroupBannerImage { get; set; }
     public bool IsNSFW { get; set; } = false;
     public bool ProfileDisabled { get; set; } = false;
 }