Simpler way to add tools

[chirino]

Describe the solution you'd like

Would be nice if you could use some macros to help define tools:

#[toolbox] // this makes the MyToolChest struct into a toolbox giving it the `get_impl_json` associated function
impl MyToolChest {
    #[add_to_toolbox("tightens a bolt")] // this adds the following function to the toolbox with the description "tightens a bolt"
    /// `bolt_location` - Location of bolt in need of tightening
    pub fn bolt_tightener(bolt_location: String) -> Result<String, std::io::Error> {
        // TODO add bolt tightening logic
        Ok(format!("I might have tightend the bolt located here: {}", bolt_location))
    }
}

This idea comes from: https://github.com/rseymour/func_me