Update set ach speed

[calbaker]

Implemented the following in

fastsim/rust/fastsim-core/src/simdrive/simdrive_impl.rs

Line 953 in 0a4b848

pub fn set_ach_speed(&mut self, i: usize) -> Result<(), anyhow::Error> {

• more descriptive variable names
• use of closures to reduce redundancy

I did this to make it easier to see how to write this section in fastsim-3.

[kylecarow]

I think the logger stuff is all I care to change, I like the rest of the changes!!