add EF core db migrations, add banned + forbidden uploads db entries, adjust authentication to include characternamehash to check for bans, prepare for message sending from client to other clients

MareSynchronosServer/MareSynchronos.API/DownloadFileDto.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace MareSynchronos.API
+{
+    public class DownloadFileDto
+    {
+        public bool FileExists { get; set; } = true;
+        public string Hash { get; set; } = string.Empty;
+        public long Size { get; set; } = 0;
+        public bool IsForbidden { get; set; } = false;
+        public string ForbiddenBy { get; set; } = string.Empty;
+    }
+}