Make create_metadata public

[Eagle941]

Current implementation of the profiler relies on parts of code extracted from cairo repo either because they require some changes or because they are private.

create_metadata is a private function in cairo-lang-runner that initialises the Metadata object of a Sierra Program. This object is used, in cairo-replay, by SierraCasmRunnerLight constructor.

For ease of compatibility with future versions of cairo, it could be useful to make create_metadata public.