feat: use own argument parser to replace structopt

structopt has been replaced by clap,
whose dependency libc does not build on newer architectures (e.g., loongarch64).
My previous attempts to port choose to clap v4 resulted in an incompatible change in allow_hyphen_values's behavior - I have reported this issue to the upstream:

- clap-rs/clap#5434
- clap-rs/clap#4187

To simplify things, I wrote my own argument parser for clap..

This change passes `cargo test` .

Author: eatradish

Cargo.lock

@@ -16,7 +16,6 @@ exclude = [
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-structopt = "0.3"
 regex = "1"
 lazy_static = "1"
 backslash = "0"