Some of the external dependencies are barely used and can be removed

[jonassmedegaard]

Hi,

A dependency on the crate rust_decimal_macros is declared for multiple of the crates part of rudof, but is only used in one of them, and there only for a few examples.
Please drop where unused, and please consider replacing the few usages with (equally compact to write) direct calls to the underlying crate rust_decimal.

See my patch for the Debian packaging of rudof for inspiration.

[angelip2303]

Hi Jonas! Thank's for pointing to a crate that is barely used in rudof. In fact, we are working on this in the refactoring of rudof. You will see that alongside with the rust_decimal_macros crate, there exist other crates that are also barely used and can be removed. I will change a bit the title of the issue and convert it into a sub-task of the issue #240.