ggml-cpu: Add CPU backend support for KleidiAI library (#11390)

* ggml-cpu: Add CPU backend support for KleidiAI library

* Add environmental variable GGML_KLEIDIAI_SME

* Add support for multithread LHS conversion

* Switch kernel selection order to dotprod and i8mm

* updates for review comments

* More updates for review comments

* Reorganize and rename KleidiAI files

* Move ggml-cpu-traits.h to source file

* Update cmake for SME build and add alignment for SME

* Remove append GGML_USE_CPU_KLEIDIAI to the GGML_CDEF_PUBLIC list

ggml/src/ggml-cpu/kleidiai/kleidiai.h

@@ -0,0 +1,17 @@
+// SPDX-FileCopyrightText: Copyright 2025 Arm Limited and/or its affiliates <open-source-office@arm.com>
+// SPDX-License-Identifier: MIT
+//
+
+#pragma once
+
+#include "ggml-alloc.h"
+
+#ifdef  __cplusplus
+extern "C" {
+#endif
+
+ggml_backend_buffer_type_t ggml_backend_cpu_kleidiai_buffer_type(void);
+
+#ifdef  __cplusplus
+}
+#endif