Remove IEquatable implementation for IRole

After a discussion, ends up this was a design choice.
Maybe we can get ContainsId to stay?

src/Discord.Net/Entities/Roles/IRole.cs

@@ -5,7 +5,7 @@ using Discord.API.Rest;
 
 namespace Discord
 {
-    public interface IRole : IDeletable, ISnowflakeEntity, IEquatable<IRole>
+    public interface IRole : IDeletable, ISnowflakeEntity
     {
         /// <summary> Gets the color given to users of this role. </summary>
         Color Color { get; }

src/Discord.Net/Rest/Entities/Roles/Role.cs

@@ -57,25 +57,6 @@ namespace Discord
             await Discord.ApiClient.DeleteGuildRoleAsync(Guild.Id, Id).ConfigureAwait(false);
         }
 
-        public override bool Equals(object other)
-        {
-            if (other == null) return false;
-            Role otherAsRole = other as Role;
-            if (otherAsRole == null) return false;
-            else return Equals(otherAsRole);
-        }
-
-        public bool Equals(IRole other)
-        {
-            if (other == null) return false;
-            else return (Id.Equals(other.Id));
-        }
-
-        public override int GetHashCode()
-        {
-            return Id.GetHashCode();
-        }
-
         public Role Clone() => MemberwiseClone() as Role;
         
         public override string ToString() => Name;