Internal module, handy functions for file and directory manipulation.
-type directory() :: file:name_all().
-type filename() :: file:name_all().
-type sql() :: string().
-spec format_bin_content(Bin) -> Result when Bin :: binary(), Ok :: {ok, sql()}, Reason :: string(), Error :: {error, Reason}, Result :: Ok | Error.
-spec read_directory(Dir :: directory()) -> Result when Reason :: string(), Error :: {error, Reason}, Ok :: {ok, [filename()]}, Result :: Ok | Error.
-spec read_system_migrations() -> Result when Reason :: string(), Error :: {error, Reason}, Ok :: {ok, directory()}, Result :: Ok | Error.