(B) Add domain exceptions

Clinics.Backend/Domain/Exceptions/Base/DomainException.cs

+namespace Domain.Exceptions.Base;
+
+public abstract class DomainException : Exception
+{
+    protected DomainException(string message) : base(message)
+    {
+
+    }
+}

Clinics.Backend/Domain/Exceptions/InvalidValue/InvalidValueDomainException.cs

+using Domain.Exceptions.Base;
+using Domain.Primitives;
+
+namespace Domain.Exceptions.InvalidValue;
+
+public class InvalidValueDomainException<TEntity> : DomainException
+    where TEntity : Entity
+{
+    private InvalidValueDomainException(string message = $"Values entered for entity {nameof(TEntity)} are invalid")
+        : base(message)
+    {
+    }
+}