ggml : replace compile definitions with version.h.in (#28364)

This commit adds a cmake version configuration file to replace the
current compile definition solution for the version.

The motivation for this change is that I made a mistake and did not take
into consideration that the compile definition means that this will
become a compiler flag for all sources in the target. This means that
when a version update happens that will recompile all sources in the
target even if they have not changed.

Refs: https://github.com/ggml-org/llama.cpp/pull/28278

ggml/src/ggml-version.h.in

@@ -0,0 +1,4 @@
+#pragma once
+
+#define GGML_VERSION "@GGML_VERSION@"
+#define GGML_COMMIT  "@GGML_BUILD_COMMIT@"