Entities: Use 'required' and '= null!' to get rid of warnings

Elwig/Models/Entities/WineAttr.cs

@@ -6,10 +6,10 @@ namespace Elwig.Models.Entities {
     [Table("wine_attribute"), PrimaryKey("AttrId"), Index("Name", IsUnique = true)]
     public class WineAttr {
         [Column("attrid")]
-        public string AttrId { get; set; }
+        public required string AttrId { get; set; }
 
         [Column("name")]
-        public string Name { get; set; }
+        public required string Name { get; set; }
 
         [Column("active")]
         public bool IsActive { get; set; }
@@ -23,13 +23,6 @@ namespace Elwig.Models.Entities {
         [Column("fill_lower")]
         public int FillLower { get; set; }
 
-        public WineAttr() { }
-
-        public WineAttr(string attrId, string name) {
-            AttrId = attrId;
-            Name = name;
-        }
-
         public override string ToString() {
             return Name;
         }