* Move axum crate into workspace subfolder
Over time I imagine we're gonna have other crates in this repo that
provide utilities or integrations for axum. This prepares for that by
moving the main axum crate into its own folder.
The README situation is a bit annoying because we want `./README.md`
for viewing the repo on github but `axum/README.md` for crates.io. For
now I've just copy/pasted it and added CI step to make sure they're
identical.
* update changelog link
* Add licenses to all examples
* is this how you install `diff`?
* or maybe this is how?
* fix readme links
* like this?
* fix cargo-deny step
* Try making root readme a symlink
* remove compare readme step
not needed since readme in repo root is now a symlink
* Revert "Add licenses to all examples"
This reverts commit ab321b7fb9.
This reworks axum's docs in an attempt to make things easier to find. Previously I wasn't a fan of those docs for the same topic were spread across the root module docs and more specific places like types and methods.
This changes it such that the root module docs only gives a high level introduction to a topic, perhaps with a small example, and then link to other places where all the details are. This means `Router` is now the single place to learn about routing, and etc for the topics like handlers and error handling.
This way there is now only one way to create a router:
```rust
use axum::{Router, handler::get};
let app = Router::new()
.route("/foo", get(handler))
.route("/foo", get(handler));
```
`nest` was changed in the same way:
```rust
use axum::Router;
let app = Router::new().nest("/foo", service);
```
