Clean up axum-debug crate (#498)

* Clean up axum-debug crate

Mostly just brings the crate more in line with the rest of the crates in
the workspace.

I've also removed the axum-debug-macros crate since axum-debug only
contained one re-export from axum-debug-macros. So we didn't need two
crates. Can always bring the "backend" crate back if we need things in
axum-debug that aren't proc-macros.

* Just testing: This should make CI fail

* Misc CI clean up

* fix intentional breakage

* fix changelog

* Remove rustfmt config for now as it gives warnings on stable

* Fix paths

axum-handle-error-extract/src/lib.rs

@@ -125,7 +125,6 @@
     clippy::option_option,
     clippy::verbose_file_reads,
     clippy::unnested_or_patterns,
-    clippy::self_named_module_files,
     rust_2018_idioms,
     future_incompatible,
     nonstandard_style,