Kernel/USB: Get all interface descriptors on enumeration

This creates all interfaces when the device is enumerated, with a link
to the configuration that it is a part of. As such, a new class,
`USBInterface` has been introduced to express this state.

Kernel/Bus/USB/USBInterface.h

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2022, Jesse Buhagiar <jesse.buhagiar@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Vector.h>
+
+namespace Kernel::USB {
+
+class USBConfiguration;
+
+class USBInterface final {
+public:
+    USBInterface() = delete;
+    USBInterface(USBConfiguration const& configuration, USBInterfaceDescriptor const descriptor, Vector<USBEndpointDescriptor> const& endpoint_descriptors)
+        : m_configuration(configuration)
+        , m_descriptor(descriptor)
+        , m_endpoint_descriptors(endpoint_descriptors)
+    {
+        m_endpoint_descriptors.ensure_capacity(descriptor.number_of_endpoints);
+    }
+
+private:
+    USBConfiguration const& m_configuration;              // Configuration that this interface belongs to
+    USBInterfaceDescriptor const m_descriptor;            // Descriptor backing this interface
+    Vector<USBEndpointDescriptor> m_endpoint_descriptors; // Endpoint descriptors for this interface (that we can use to open an endpoint)
+};
+
+}