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/MareSynchronosServer/Models/ForbiddenUploadEntry.cs

@@ -0,0 +1,11 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace MareSynchronosServer.Models
+{
+    public class ForbiddenUploadEntry
+    {
+        [Key]
+        public string Hash { get; set; }
+        public string ForbiddenBy { get; set; }
+    }
+}