Derives a plugin from a raw working project (SDD 10).
mix capstone.plugin.derive cacheReads the named entry from priv/baselines.exs — its raw project path, the
baseline it is derived_from and the names its placeholders replace — and
writes the templated plugin to priv/meta/meta_<name>/.
A directory whose name starts with meta_ carries placeholders; one that does
not is a raw project. cache_component in, meta_cache out.