feat: add request validation

src/request.validation/Severity.cs

@@ -0,0 +1,25 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Validation;
+
+/// <summary>
+/// Specifies the severity of a rule.
+/// </summary>
+public enum Severity
+{
+	/// <summary>
+	/// Error
+	/// </summary>
+	Error,
+
+	/// <summary>
+	/// Warning
+	/// </summary>
+	Warning,
+
+	/// <summary>
+	/// Info
+	/// </summary>
+	Info,
+}