First commit. Include junk from template to remove

src/Application/Common/Behaviours/ValidationBehaviour.cs

@@ -0,0 +1,35 @@
+using ValidationException = Hutopy.Application.Common.Exceptions.ValidationException;
+
+namespace Hutopy.Application.Common.Behaviours;
+
+public class ValidationBehaviour<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
+     where TRequest : notnull
+{
+    private readonly IEnumerable<IValidator<TRequest>> _validators;
+
+    public ValidationBehaviour(IEnumerable<IValidator<TRequest>> validators)
+    {
+        _validators = validators;
+    }
+
+    public async Task<TResponse> Handle(TRequest request, RequestHandlerDelegate<TResponse> next, CancellationToken cancellationToken)
+    {
+        if (_validators.Any())
+        {
+            var context = new ValidationContext<TRequest>(request);
+
+            var validationResults = await Task.WhenAll(
+                _validators.Select(v =>
+                    v.ValidateAsync(context, cancellationToken)));
+
+            var failures = validationResults
+                .Where(r => r.Errors.Any())
+                .SelectMany(r => r.Errors)
+                .ToList();
+
+            if (failures.Any())
+                throw new ValidationException(failures);
+        }
+        return await next();
+    }
+}