Moved PE-specific functions into their respective impl

[Jujstme]

No description provided.

[AlexKnauth]

Something about how iter is used here feels off. As... for lack of a better word, a "static method"... used as Symbol::iter instead of the object.iter pattern used everywhere else in Rust.

[Jujstme]

What about renaming it something like .read_from(process: &Process, module: impl Into<Address>)?

[AlexKnauth]

I think it was fine as it was with pe::symbols(process, module_address). Symbol::read_from(process, module_address) doesn't feel right for a function returning an iterator because there's no indication of plural or iteration.